Sunless Sea

Sunless Sea

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Sunless Sea: Troubleshooting
By failbetterfuzz
Welcome to the official Sunless Sea: Troubleshooting guide. If you are having technical issues with the game then you should find the help you need below.
Reporting Bugs
Hello! If you’re reading this, you’ve probably found a bug and want to report it to us. Before you do, please take a moment to check out this troubleshooting guide. The vast majority of technical issues that players experience are listed here, along with steps to fix the problem.

If you cannot resolve your issue using this guide then please read the sections below on core information and graphical/text issues so you know what to include in your report before sending it to The more information we have the quicker we’ll be able to resolve the issue.

Bug report core information
One bug per report please! Please include the following:
  • Clearly summarise the bug in one or two sentences. Explain where you were in game and what you were doing when you experienced the issue. Please give reproduction steps if possible.
  • The build you are using, visible on the title screen. (Current build:
  • Platform and tech specs:
    • OS (e.g. Windows, MacOS, Linux)
      • Version (e.g. XP, Windows 10, El Capitan, Sierra, Ubuntu, Mint, etc.)
      • 64/32bit
    • RAM
    • CPU
    • GPU
  • Troubleshooting steps you’ve already undertaken
  • Always attach your output / player log
  • Other relevant attachments (screenshots/video for graphical and text issues, and crash logs and save files where applicable) – please note that our ticketing system has a 7MB file size limit, so please compress large files such as video clips or zip them up

Graphical and Text Issues
If you find typos or grammatical errors, please include a screenshot as this often helps us locate the issue in our CMS.
Please include a screenshot where possible for any graphical issues. Please also tell us the resolution you are running the game at (to view this from the Title Screen go to Options > Video Settings). Videos can also be helpful but our ticketing system has a 7MB file size limit, so please compress video files or zip them up. If the video is still too large for you to attach to a ticket, we are happy to look at videos you have uploaded on YouTube or Twitch, but please link us directly to the relevant time stamp where the issue occurs.
System Requirements
First, please make sure your system meets the requirements for the game. Check the System Requirements on Sunless Sea's Steam store page. The game has the same requirements on Steam, GOG and Epic.

Video Card Drivers
Please make sure your video card drivers are fully up to date. This is especially important for Intel integrated GPUs and it’s best to check the manufacturer’s website than rely on Windows:

Intel HD Graphics[]
Nvidia GeForce[]
Other Nvidia cards[]
AMD/ATI cards[]

If you have more than one graphics card Unity3D can sometimes fail to select the best one. Usually updating your graphics drivers or creating a profile for Sunless Sea in your graphics driver's control center can help.

You can check which graphics card Sunless Sea is using right at the top of your output log - look for 'Renderer'.

If you are experiencing exceptionally poor performance, it could be that your graphics card has defaulted to the Basic Render Driver. Microsoft Basic Render Driver is a fallback driver that Windows uses if it can not find the drivers for the graphics card.

You either need to enable your dedicated graphics card or update your graphics driver, there's a great guide for both here[]
Sound Card Drivers
Sunless Sea uses the FMOD audio libraries and unfortunately FMOD crashes if the sound card is not installed properly. A good indication of a sound driver issue is when it crashes before the main menu is displayed.

Your output log will reference the issue with FMOD though it does not look like a normal exception so use Ctrl+F to look for FMOD.

Ensure your sound card drivers are up-to-date update via the vendor's website. You should be able to find information about the sound card vendor in the Windows Device Manager.

Additionally there are sound issues with Windows 10 which will prevent the game from starting, though these are not specific to Sunless Sea, Please follow these instructions from Microsoft to fix sound card issues in Windows 10.

While most FMOD issues are resolved by updating the sound card, sometimes they can be a result of applications having exclusive access to your sound device. When this happens you'll typically see the following message, or similar, in the Output log:
FMOD failed to initialize. This may be because your sound card is configured to give applications exclusive access, thus preventing Unity from using this device. You can change this in Control Panel > Audio Devices and Sound Themes > Playback Device > Properties > Options ... : "Soundcard does not support the minimum features needed for this soundsystem (16bit stereo output)."

Disabling the Exclusive Mode options in Windows Sound Preferences can resolve this by preventing audio applications from taking exclusive control of the driver. To do this, do the following:
  1. Open Control Panel > Hardware and Sound > Sound and click on the Playback tab
  2. Select your speaker/headphones from the list of audio devices and then click Properties
  3. In the Properties window, go to the Advanced tab and deselect the option to "Allow applications to take exclusive control of this device"
  4. Click OK to Apply the settings
  5. Back in the Sound window, click on the Recording tab and repeat steps 2-4
  6. Once complete, restart your computer for the changes to take effect.

If that doesn’t work go to Control Panel > Hardware and Sound > Sound and go through the Playback and Recording tabs to disable any additional devices before giving Sea another try.
Where to find your save files
Intermittent errors that occur regularly in a particular save game can be difficult for us to identify, so occasionally we may ask you to provide us with your save files which are located in the saves directory in the following locations depending on your operating system:

%userprofile%\AppData\LocalLow\Failbetter Games\Sunless Sea\saves

~Library/Application Support/unity.Failbetter Games.Sunless Sea/saves

Linux / Steam Deck
~/.config/unity3d/Failbetter Games/Sunless Sea/saves

If you are playing in Unforgiving Mode then you should just see two autosave json files in the saves directory. Ensure you send both to us when contacting support.
  • autosave.json
  • autosave_fallback.json

If you are playing in Merciful Mode then will see additional json files, each with their own fallback file. The Autosove and Autosave_fallback files are still the most relevant to us, but you may want to zip up the entire saves directory so that we have access to everything.

Hidden Directories

If you cannot find the file paths listed above then it could be because the directories are hidden.

The AppData folder is generally a hidden one, so if you've not got Windows Explorer set to display hidden files then it's hiding from you.Try these steps:
  1. Go to C:\Users\[username] - replace [username] with your actual user name.
  2. On Windows Explorer, select the View tab and then click Options
  3. The Folder Options window will pop up - select the View tab
  4. Under Files and Folders, you'll see the Hidden files and folders directory and two radials - make sure the Show hidden files, folders and drives radial is selected

  5. Click Apply and then OK
  6. Close that down - you should now see the AppData folder in Windows Explorer
You should be able to find your way from there. Alternatively, you should just be able to copy the file location straight into the Windows Explorer bar and it'll take you straight there C:\%userprofile%\AppData\LocalLow\Failbetter Games\Sunless Sea\saves

If you don't see it after turning the hidden files to 'Show', then it could be that all of this is on a different drive, like a D drive for example, but the above steps will apply just the same to any alternative drives you have.

The ~/Library is hidden by default. Here are some steps to help you locate it:
  1. Open the Finder
  2. Choose Go from the menu bar
  3. Choose Go to Folder (or Shift-CMD-G)
  4. Type ~/Library into the text box and press go - you should now see and be able access the contents of the ~/Library which were previously hidden from sight.

  1. Open the Terminal (found in Finder > Applications > Utilities)
  2. In Terminal, paste the following:
    defaults write AppleShowAllFiles YES
  3. Press return
  4. Hold the ‘Option/alt’ key, then right click on the Finder icon in the dock and click Relaunch. This will show all hidden files.

On Sierra and later OSX versions you can also use the following shortcut when in Finder. Press once to show hidden files and again to hide them.

Locating the correct Library on MacOS

If you are copying the file path given above, make sure you include the ~/ before Library, otherwise you will be sent to the wrong location.

Entering Library into the Finder will take you here:

Entering ~/Library into the Finder takes you to a completely different directory:
Where to find your output / player log
Often, to track down a bug, we need to take a look at your output log (or player log on MacOS and Linux) . Here’s how to find it on your operating system.

Please note: the log file is replaced each time you run the game, so it’s important to submit the file immediately after the session in which you experience the bug.

  1. Go to the directory where you installed Sunless Sea. This will probably be in the following location:
    • C:\Program Files (x86)\Steam\SteamApps\common\SunlessSea (if you’re using Steam)
    • C:\Program Files (x86)\GOG Galaxy\Games\Sunless Sea (if you’re using GOG Galaxy)
    • C:\Program Files (x86)\Epic Games\SunlessSea (if you’re using Epic Games Launcher)
  2. Open the Sunless Sea_Data directory.
  3. Your log file is output_log.txt.
  4. If there is no log in this location, go to C:\%userprofile%\AppData\Local\VirtualStore\Program Files (x86)\Sunless Sea\Sunless Sea_Data. The log file will be there.

File Location: ~/Library/Logs/Unity
  1. Activate the Finder.
  2. Use the Go menu and choose Go To Folder, or press Cmd-Shift-G.
  3. Type /Users/[USERNAME]/Library/Logs/Unity, replacing [USERNAME] with your sign on username.
  4. Your log file is Player.log.

Linux / Steam Deck
  1. Navigate to ~/.config/unity3d/Failbetter Games/Sunless Sea
  2. Your log file is Player.log.

Hidden Directories

If you cannot find the file paths listed above then it could be because the directories are hidden. Please see the Hidden Directories information within the Where to find your save files section above.
Where to find crash logs
If you experience a crash then crash files are auto-generated and should appear in the install directory (the name of the folder will be the date on which the crash occurred). These files can be helpful to us when looking for the root cause, so please send them to Any crash logs will usually be found in the following location depending on your operating system:

C:\Program Files (x86)\Steam\SteamApps\common\SunlessSea (if you’re using Steam)
C:\Program Files (x86)\GOG Galaxy\Games\SunlessSea (if you’re using GOG Galaxy)
C:\Program Files (x86)\Epic Games\SunlessSea (if you’re using Epic Games Launcher)

~Library/Application Support/Steam/steamapps/common/SunlessSea

Corrupt Game Files / Installation problems
Occasionally game files (as opposed to save files) can become corrupted during installation or updates. This will present itself in a few ways, but most commonly in hanging or crashing (usually with the game closing before you even get to the title screen). Verifying the game files usually fixes these issues. To do this take the following steps:

  1. Right click on Sunless Sea in your library
  2. Select Properties
  3. Click on the Installed Files tab
  4. Click Verify Integrity of Game Files

  1. Select your game from your library
  2. Select the More button
  3. Highlight Manage Installation and select Verify / Repair
  4. Click Verify Game

  1. Locate the game in your library
  2. Select the Settings Menu button next to the game's icon (three horizontal dots)
  3. Select Manage
  4. Click Verify

It's rare, but sometimes the installation may be broken even though all the files pass the validation. In these situations it's best to uninstall and reinstall the game, then verify the integrity of the files after re-installing.
Corrupt Save Files
Sunless Sea save files can sometimes become corrupt when the game shuts down unexpectedly due to a hardware crash, a sudden power cut, or a Windows update that cannot be cancelled while the game is saving.

In April 2019 we introduced the autosave_fallback.json file to help with save file corruption. If your autosave.json file becomes corrupt then the fallback file will repopulate the autosave file with its data the next time you load your save.

The autosave_fallback file has helped resolve the vast majority of corruption issues, but on rare occasions both save files will become completely nullified and sadly there is no way to recover save games in this state. You’ll need to delete both files before you're able to create another save game.

We recommend checking out your Steam cloud saves for Sunless Sea on the Steam server. Steam usually keeps multiple saves on its servers, so while the latest cloud save will be the corrupted one, there may be earlier saves that you could recover. You’ll need to turn Steam cloud saving off for Sea before copying those save files into your saves folder and running the game again - otherwise it would re-download the corrupted files. You can check out all your Steam cloud saves here.

If you're experiencing frequent hardware issues then we recommend taking your machine to a professional so the issue can be diagnosed. However, until you are able to do that it might be a good idea to make regular manual back-ups of your save files after each play session. For details please see the Manual backups of save files heading in the Low Performance / FPS section below.
Corrupt Resource Files
If on loading your save file you see your ship or zub on an endless empty sea then this is indicative of corrupted game resource files.

Take the following steps to resolve the issue:
  1. Ensure cloud saving is turned off, otherwise Steam / GOG / Epic will download the files into your saves folder again
  2. Navigate to the following location depending on your operating system:
    • Windows: C:\%userprofile%\AppData\LocalLow\Failbetter Games\Sunless Sea
    • MacOS: ~Library/Application Support/unity.Failbetter Games.Sunless Sea
    • Linux: ~.config/unity3d/Failbetter Games/Sunless Sea
  3. Make a back-up of the saves folder - copy it to your desktop or some other location
  4. Delete all files except the saves directory and the users folder, if it is present
  5. Launch the game
  6. From the title screen select Load Game, select the autosave file (or your manual save file) and then click the Load button
Epic Games Launcher: Black Screen on launch
If you experience a black screen when launching the game through the Epic Games Launcher, then check your output/player log for the following error:

DllNotFoundException: C:/Program Files/Epic Games/SunlessSea/Sunless Sea_Data/Plugins/EOSSDK-Win32-Shipping.dll at (wrapper managed-to-native) Epic.OnlineServices.Platform.PlatformInterface:EOS_Initialize (intptr) at Epic.OnlineServices.Platform.PlatformInterface.Initialize (Epic.OnlineServices.Platform.InitializeOptions options) [0x00000] in <filename unknown>:0 at EpicOnlineServicesSDK.OnInitialize () [0x00000] in <filename unknown>:0 at UnityEngine.Events.InvokableCall.Invoke (System.Object[] args) [0x00000] in <filename unknown>:0 at UnityEngine.Events.InvokableCallList.Invoke (System.Object[] parameters) [0x00000] in <filename unknown>:0 at UnityEngine.Events.UnityEventBase.Invoke (System.Object[] parameters) [0x00000] in <filename unknown>:0 at UnityEngine.Events.UnityEvent.Invoke () [0x00000] in <filename unknown>:0 at EpicOnlineServices.Initialize () [0x00000] in <filename unknown>:0 at EpicOnlineServices.Awake () [0x00000] in <filename unknown>:0

If you see this error then there's an issue with the EOSSDK-Win32-Shipping.dll file. This issue is usually not a problem with the file itself, rather it's down to missing Microsoft Visual C++ Redistributable files on the computer the game is being run from. (Note: if you see a different error then check the Corrupt Save Files and Other Black Screen Issues sections of this guide).

There's several things to try, but in our experience with this problem so far it tends to be the Microsoft Visual C++ Redistributable that's the root cause (Solution #4 below).

Solution #1: Corrupt Win32-Shipping.dll
There's a possibility that the dll is corrupt. Please try these steps first:

  1. Navigate to the Plugins directory within the game's installation folder. Depending on where you install your Epic games it will be something like: C:\Program Files (x86)\Epic Games\SunlessSea\Sunless Sea_Data\Plugins
  2. Delete the EOSSDK-Win32-Shipping.dll
  3. Open the Epic Games launcher and go to your library
  4. Click on the Settings Menu button next to the Sunless Sea icon (three dots . . . )
  5. Select Manage
  6. Click Verify
  7. Launch the game again

Solution #2: Place the Win32-Shipping.dll file in the installation folder
If that didn't work please try the following:
  1. Go to C:\Program Files (x86)\Epic Games\SunlessSea\Sunless Sea_Data\Plugins
  2. Copy the EOSSDK-Win32-Shipping.dll and paste it into C:\Program Files (x86)\Epic Games\SunlessSea
  3. Launch the game

If the game can't find the EOSSDK-Win32-Shipping.dll in the Plugins folder it will then look for it in the root installation folder so that will enable the game to run. However if you still run into issues then it looks like this is a dependency issue Microsoft Visual C++ Redistributables.

Solution #3: Ensure Windows is fully up to date
Make sure Windows is fully up to date. Certain Windows updates can change or replace .dll files, so they are not available when another program wants to use them. Select the Start button > select Settings > Update & security > Windows Update, and see if there are any pending updates.

Your machine should restart as part of any updates that are installed but if not, make sure you restart your machine before attempting to run the game again.

Solution #4: Reinstall the Microsoft Visual C++ Redistributable
If that doesn't work then it's likely the Microsoft Visual C++ Redistributable required is either corrupt or missing on your PC and you'll need to reinstall it. You can locate and download this file here[].

Regardless of whether you are using a 32-bit or 64-bit version of Windows, you will need to download the 32-bit version (vc_redist.x86.exe). After this completes installing, restart your PC.

As recommended by Epic, if you continue to have this error we recommend you reach out to Microsoft Support[] as they’ll be able to help you out.
Other Black Screen Issues
There are multiple causes of black screen issues. To diagnose them you need to look for errors in the output log. Details of where to find this on your machine can be found in the section: Where to find your output / player log.

Once you've located your output log you need to open it in a text editor and look for errors/exceptions. We recommend Notepad++[], but make sure Word Wrap is on! (Go to View and click Word Wrap to select it).

SteamAPI_init() failed
If you see
(SteamAPI_init() failed)
in your output/player logs then the Steam app may not be running correctly. If you see this try the following:
  • Try restarting Steam.
  • Try logging in and out of Steam and restarting.
  • Check your Antivirus or Firewall settings. Updates have been known to put games in the AV/Firewall sandbox/quarantine. We recommend making an exception for Steam / GOG / Epic in your anti-virus to resolve this issue, rather than turning your anti-virus off.

If the above suggestions fail then the error is probably due to the Windows account you are not having administrative access. All you have to do is switch to your Windows account with “Administrative Access” and the issue will be resolved.

Steam_appid.txt file is present
If you see
Cannot continue, steam_appid.text file is present. Quitting...
in your output/player logs then the steam_appid.txt file is present in the Sunless Sea Data folder and the game will not run. If you see this try the following:

  1. Right click on Sunless Sea in your library
  2. Select Properties
  3. Click on the Installed Files tab
  4. Click Browse - this will open the install directory
  5. Look for a file named 'steam_appid.txt' - it may be within the Sunless Sea_Data directory - when you find it, delete the file
  6. Go back to Sunless Sea in your Steam library, right click it and select Properties.
  7. Click on the Installed Files tab
  8. Click Verify Integrity of Game Files
  9. Relaunch Sunless Sea

Microsoft Media Foundation
If you see
'Initializing Microsoft Media Foundation failed.'
in your output log then either:
  1. Windows Media Player is not enabled
  2. Microsoft Media Foundation is not installed on your machine
  3. A newer version of Microsoft Media Foundation is required

First, ensure Windows Media Player is enabled. Sometimes it's not enabled automatically on some Windows operating systems or after some updates.

  1. Open the Start menu
  2. Open the Control Panel
  3. Launch Programs and Features
  4. Click “Turn Windows features on or off” in the left side of the window
  5. Look for the “Media Features”
  6. Expand the “Media Features”
  7. Check the “Windows Media Player”

  8. Click OK
  9. Restart your computer

If the Windows Media Player is already enabled or you still cannot run the game after enabling it then it is likely that Microsoft Media Foundation is not installed on your machine, or it needs updating.

Please install the Media Feature Pack[] for your version of Windows. The Media Feature Pack that comes up upon a simple google search is NOT the correct version for Windows 10 after the Creators Update – it’s necessary to look for the newest Media Feature Pack from April 2017 (available here[]).

If you are on Windows 10 N, Sunless Sea may not run even after installing Microsoft Media Foundation pack and re-enabling Windows Media Player. Reinstalling Windows 10 resolves the issue.

Unity games on Windows 10 1709
If you see the following error in your output/player logs then this is due to a bug that was released in Windows 10 1709 that is causing this issue with a lot of Unity games.
IndexOutOfRangeException: Array index is out of range. at UnityEngine.Display.RecreateDisplayList (System.IntPtr[] nativeDisplay) [0x00000] in :0
There is an excellent thread about it on Steam with lots of advice on how to resolve the issue. Check it out the OP’s trouble shooting steps as it has resolved the issue for a lot of people.
Fatal Error: Backup Failed
While saving an additional backup file (autosave_bkp.json) is briefly created as a failsafe before being deleted. Occasionally an error can occur while copying the file and you’ll see an in-game pop-up explaining that the backup failed and you need to contact support:

On clicking Continue you’ll be kicked out of the game to the title screen which will look broken:

Before contacting support, try these steps to resolve the issue first:

  1. Turn off Steam / GOG / Epic cloud saving
  2. Navigate to the saves directory on locallow
  3. Make a backup of the autosave_bkp.json file somewhere on your PC - if these steps do not work you and you need to contact support then we may need this file
  4. Delete the autosave_bkp.json file from the save folder
  5. Launch Sunless Sea and load your save file
  6. Once in game trigger a save by undocking and redocking at your current port

If this does not resolve your issue and you start to see another error (below) which mentions missing data when loading the save file then please get in touch with support to see if we can help. You will need to send the following:
  • output log
  • autosave.json
  • autosave_bkp.json
  • autosave_fallback.json

Occasionally there can be issues with the bkp file continuing to download itself once cloud saving is re-enabled. If this happens to you then you’ll need to take the following steps to resolve the problem:

  1. Open your Steam client, click Steam in the top left corner of the window and select Settings
  2. Open the Cloud tab and uncheck the option “Enable Steam Cloud synchronization”. Click OK
  3. Navigate to your saves folder and delete the autosave_bkp file
  4. Run the game and load your save file
  5. Undock and redock in order to save the game
  6. Close the game down
  7. Do not close Steam down as you normally would, instead press Ctrl Alt Delete and open the Task Manager
  8. Locate the Steam Client Bootstrapper, click on it and then select End Task. This should close all steam related processes
  9. Open Windows Explorer and navigate to the Steam userdata folder: C:\Program Files (x86)\Steam\userdata
  10. Once in the userdata folder you should have a folder corresponding to your SteamID. Inside that folder you’ll need to locate the AppId folder for Sunless Sea which is 304650
  11. Open the AppId folder 304650 and delete everything inside (it may just be a remotecache.vdf file)
  12. Restart Steam
  13. Re-enable Cloud saving
  14. Find Sunless Sea in your library and click Play
  15. You'll now see a Cloud Sync Conflict pop-up

  16. Select the option to upload the Local files up to the Steam Cloud
Crash when launching from Steam client
If you experience a crash when launching Sunless Sea from the Steam client but not when launching from the .exe then it's possible this is a result of your DPI being set higher than 100%, with the game running on fullscreen. We understand you probably want to keep your DPI setting as is, however you may need to change the DPI when you play Sunless, in order for it to work properly.

To resolve this issue, change your DPI back to 100% or whatever is recommended for your PC (from the Start menu select Settings > System > Display > Scale and layout).
Crashes on launch: Citrix
If you experience a crash when first launching the game then check for this error in your logs:
If you see this it's possible another application is interfering with the game.

Citrix Workstation (formerly Citrix Receiver) causes this issue with a number of Unity games. Try uninstalling Citrix, restarting your machine and launching Sunless Sea again (we have reports from players that Sunless Sea will continue to play without issue once the latest version of Workstation is reinstalled).

If you are unsure if you have Citrix then you can check for the program in your Control Panel:

Or if the app was installed via the Microsoft store you'll be able to find it on the Start menu:
Crash on launch: Corrupted Font Files
If you experience a crash on launch and you see an error that starts with
Crash!!! SymInit: Symbol-SearchPath:
in your player log, you should check to see if you have Citrix installed as per the instructions in the section above.

If you don’t have Citrix installed, then the Symbol-SearchPath crash is likely to be a result of corrupted font files on your machine. This is a fairly common bug which affects numerous Unity games.

Solution #1
First, ensure that your graphics card drivers and direct X are full up to date before trying to run the game again (see section ‘Video Card Drivers’ above).

Solution #2
If you're playing on Windows 10 try running in compatibility mode for Windows 8.

Solution #3
If the above solutions don’t work then try restoring default font settings:
  1. Make sure no programs are currently running
  2. Go to Control Panel > Fonts > Font settings
  3. Click the "Restore default font settings" button
  4. Restart your machine and attempt to play Sunless Sea

Solution #4
If the above solutions don’t work, try deleting the font cache files:
  1. Make sure no programs are currently running
  2. Open Windows File Explorer and go to "C:\Windows\ServiceProfiles\LocalService\AppData\Local" (it's a hidden folder so it's best to just copy-paste the file path. If the full file path doesn’t work try C:\Windows\ServiceProfiles\LocalService\AppData)
  3. Attempt to delete any files whose names start with "FontCache" (some will be write-protected; you can skip those)
  4. Restart your machine and attempt to play Sunless Sea

Solution #5
If the above solutions don’t work, then try deleting the hidden UNCL.ttf file:
  1. Make sure no programs are currently running
  2. Open Windows File Explorer and select the View tab
  3. Click Options
  4. Click the View tab on the Folder Options pop-up window that opens
  5. Ensure "Show hidden files, folders and drives” radial is selected
  6. Uncheck "hide protected operating system files" checkbox (we recommend you undo this step later as this exposes Windows OS files which can break your computer if deleted)
  7. Click Yes on the confirmation pop-up
  8. Click Apply and OK
  9. Copy the path "C:\Windows\Fonts" into the top of the Windows File Explorer
  10. If there's a file in there called "UNCL.ttf" or similar, delete it (it may be called PR Uncial Alternative Capitals)
  11. Remember to go back and tick the "hide protected operating system files" checkbox
  12. Restart your machine and attempt to play Sunless Sea

Solution #6
If the above solutions don’t work, then it's possible you have a corrupted font but can't find it. Follow these steps to replace it.
  1. Uncheck "hide protected operating system files" as directed in Solution#5
  2. Download UNCL.ttf (you can download it here[]
  3. Drag the UNCL.ttf file from your Downloads folder into the Font directory (C:\Windows\Fonts) - it will either install immediately or ask you if you want to replace the already installed version, in which case select Yes (it may be referred to as PR Uncial Alternative Capitals)
  4. Now locate the newly installed/replaced UNC.ttf file and delete it.
  5. Remember to go back and tick the "hide protected operating system files" checkbox
  6. Restart your machine and attempt to play Sunless Sea

Solution #7
If the above solutions don’t work and you still cannot find the UNCL.ttf file, then here's a last resort:
  1. Uncheck "hide protected operating system files" as directed in Solution#5
  2. Make a backup copy of the Fonts directory (to your desktop, for example)
  3. Delete everything Windows will let you delete in the original Fonts folder
  4. Now Copy every file from the backup Fonts folder you created back into the original Fonts folder.
  5. The UNCL.ttf file should be there - delete it
  6. Remember to go back and tick the "hide protected operating system files" checkbox
  7. Restart your machine and attempt to play Sunless Sea

If none of the above steps can solve the issue then we are unlikely able to offer a better solution at this time. The problem is frequently reported across several popular Unity titles without much sign of a solution as of yet.
Low Performance / FPS
If you are experiencing poor performance in game then the first thing to do is make sure your graphics card is up to date. Please see the Video Card Drivers section above.

If you are experiencing exceptionally low FPS it could be that your graphics card has defaulted to the Microsoft Basic Render Driver. Please see the Video Card Drivers section above for more details.

If your graphics card is up to date and it is not defaulting to the Basic Render Driver when running Sunless Sea, then try setting the Graphics Quality to a lower setting:
  1. From the Title Screen select Options
  2. Select Video Settings
  3. Change Quality from Sublime to Adequate
  4. Click Accept

We also recommend making sure your Windows updates are in fact up to date and that you close down any non essential programs whilst playing Sea.

Hardware Issues
It's normal to experience hardware issues from time to time; crashes, Windows updates that can't be cancelled, sudden power cuts, etc. However if you are experiencing consistent and repeated hardware problems (crashes, hangs, blue screen of death) then we really recommend taking your rig to an IT professional to have it looked at. Following the advice above will only help so much. If you have underlying hardware issues then you need to eliminate the root cause of the problem.

Manual backups of save files
If your computer crashes when the game is saving then this can lead to corrupted save files - advice on repairing save files is given in the Black Screen Issues: Corrupt Save Files section above.

If you're experiencing frequent hardware issues then it might be a good idea to make regular manual back-ups of your save files after each play session. For Sunless Sea the easiest way would be to zip up your saves directory and store the backup in a safe place (see the Where to find your save files section above).
MacOS: Sunless needs updating
After upgrading your iOS version to Catalina or later, you may see an error when trying to run Sunless Sea:

This is related to Apple no longer supporting 32-bit apps and it’s likely that the version of Sunless Sea on your machine - and indeed your installed version of the Steam client - is the 32-bit version. Take the following steps to download both the 64-bit versions of Steam and Sunless Sea:
  1. Uninstall Sunless Sea from your Steam library
  2. Uninstall the Steam client
  3. Download the Steam client here and install it:
  4. Once you've installed Steam and logged back in, download Sunless Sea. The 64-bit version will automatically be installed and you should be good to go
MacOS: Steam error after downloading updates
Occasionally a Steam error is seen when trying to launch the game after an update.

If you see this please uninstall the game via Steam and then reinstall (don't worry, it just uninstalls the game files, your save files are in a separate location and are not removed when the game is uninstalled, so you will not lose your progress).
MacOS: Corrupted Game Text
Since late 2019 we've had a handful of players report and issue to us where the game text looks corrupted and is completely unreadable. We're not sure of the underlying cause just yet, but it seems to be something that's isolated to MacOS and is most prevalent on Mojave.

Sometimes the corruption even extended to the background on the title screen:

One of our players who recently experienced this issue has reported that they were able to resolve this by "changing resolution settings back and forth". Since we understand that you can't really tell what the buttons say we have included screenshots in the steps below:

  1. Once the game has loaded and you are on the title screen, select Options (4th button from the top)

  2. Then select Video Settings (3rd button from the top)

  3. Once on the Video Settings menu, try altering the resolution a few times to see if it makes any difference

  4. If resolution doesn't do anything, try also changing the UI and Font scale along with resolution to see if that helps

If it's easier to test the effect of these changes from within the game rather than from the title screen, then follow the same steps just press the 5th button from the top in step 1, instead of the 4th.

N.B. It is worth noting that a couple of our players have reported they had to repeat these steps a few times before they saw results (and on one occasion it lead to the game shutting down), so please persist.
Epic Games Launcher: Zubmariner DLC
If you purchase and play Sunless Sea on the Epic Games Store and then later purchase the Zubmariner DLC, it will occasionally fail to download correctly. If this happens uninstall the Sunless Sea completely and then reinstall the game. The Zubmariner DLC will download at the same time Sunless Sea is reinstalled.
Blurry Font
Blurry fonts are sometimes seen when running the game on certain aspect ratios in fullscreen mode (e.g. running at a resolution of 1680x1050, which is a 16:10 aspect ratio, at fullscreen on a 1920x1080 monitor). To get rid of the blur, adjust the UI Scale and Font Scale settings from within the Options menu until you find a setting that works for your resolution.
Minimised game window
Some players have experienced the game opening at a resolution of 0 x 0 pixels and are therefore unable to play (audio can be heard, but nothing is displayed). If this happens to you, please try the following:

  1. Go to ~/.config/unity3d/Failbetter Games/Sunless Sea/
  2. Open the prefs file and scroll right to the bottom
  3. Find <pref name=”Screenmanager Resolution Height” type=”int”>xxx</pref> and change the value of xxx to 720
  4. Find <pref name=”Screenmanager Resolution Width” type=”int”>xxx</pref> and change the value of xxx to 1280
  5. Save the file and close it before launching the game

  1. Go to C:\Program Files (x86)\Steam\steamapps\common\SunlessSea
  2. You’ll see the Sunless Sea application. Please press and hold down Ctrl, then double click on the game. Keep Ctrl pressed down the whole time until the Sunless Sea Configuration window opens (if it doesn’t open first time, just double click again)

  3. Select a resolution from the drop down list
  4. Click play to launch Sea
Second enemy cannot be targeted with firing solution
If you cannot fire on an enemy because your firing solution seems to be stuck on a different enemy just off screen, try using Tab to re-target onto the second enemy.

In the majority of cases this will resolve the issue. However if it doesn't then it suggests something has gone wrong with the game files. Reinstalling and then verifying the game files will resolve this:

  1. Uninstall the game
  2. Reinstall
  3. Once installation is complete, verify the game files:

  1. Right click on Sunless Sea in your library
  2. Select Properties
  3. Click on the Installed Files tab
  4. Click Verify Integrity of Game Files

  1. Select your game from your library
  2. Select the More button
  3. Highlight Manage Installation and select Verify / Repair
  4. Click Verify Game

  1. Locate the game in your library
  2. Select the Settings Menu button next to the game's icon (three horizontal dots)
  3. Select Manage
  4. Click Verify
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A Blunt Stick Aug 12, 2021 @ 6:48am 
Fantastic guide folks. Thank you. :unterzee: