Editing XLS files causing crash

[Robert]

As the title says, since the latest update, the game will not start if I have made any changes to the XLS files
The launcher is skipped, and the screen remains black despite the DWS logo sound playing
I was hoping to alter the deck guns to make them powerful
I have done these edits before, but the new update appears to be locking
Does anyone have any advice?

[Foxxhound]

Are you changing the files in the game directory instead of the AppData files? I remember back in Early Access this game doesn't like you changing the original files or even copies of the originals. I had to create brand-new blank spreadsheets in a folder dedicated to my mod, then copy/paste rows from the original spreadsheet into the new one I created in my mod's folder.

I also vaguely remember the game having issues if you try to run the game with the files already open. It's been a while so I don't know for sure. There are much more knowledgeable modders who can correct me on this.

[DarkRaven]

Originally posted by Foxxhound:

Are you changing the files in the game directory instead of the AppData files? I remember back in Early Access this game doesn't like you changing the original files or even copies of the originals. I had to create brand-new blank spreadsheets in a folder dedicated to my mod, then copy/paste rows from the original spreadsheet into the new one I created in my mod's folder.

I also vaguely remember the game having issues if you try to run the game with the files already open. It's been a while so I don't know for sure. There are much more knowledgeable modders who can correct me on this.

In addition, at least in 2025.1 and prior, UBOAT doesn't like xlxs files saved in LibreOffice.

[Robert]

Originally posted by DarkRaven:

In addition, at least in 2025.1 and prior, UBOAT doesn't like xlxs files saved in LibreOffice.

Before the latest update, I had been using LibreOffice to edit the xlxs files without problem

I looked at the files in the AppData folder, but they are dat files, and I don't know how to edit them safely

[link]

Originally posted by Robert:

Originally posted by DarkRaven:

In addition, at least in 2025.1 and prior, UBOAT doesn't like xlxs files saved in LibreOffice.

Before the latest update, I had been using LibreOffice to edit the xlxs files without problem

I looked at the files in the AppData folder, but they are dat files, and I don't know how to edit them safely

the .dat files are just the unpacked / read version of the .xlsx files, they are rebuilt every time there is a byte change to a .xlsx. think of them as just a temp file which is quicker to read by the game.

restore your games files first

then what are you trying to edit? modifying the game files directly even .xlsx is not a recommended approach for datasheet edits, it would be better to create a local mod with the changes you want < this is less prone to errors in loading and has different error handling.

what does your output log say?

[Robert]

I can't find an output log, so I don't know what it might say
I try to alter the torpedoes to make them powerful and homing
I have also tried removing the need for an officer when conducting research
Both these worked before the 2026 update

[r6751]

I use Google sheets for editing datasheets. No issues.