How To Fix "LOOKUP FAILED!" (Fallout 4)

One of the most annoying visual bugs in the game, it can prevent the player from seeing important information about weapon, power armor, and armor modifications, as well as other things. This is how to fix it.

Issue #1 - Creation Club

When playing Fallout 4 on any platform, Creation Club always is present and can make the game more entertaining. However, it is notorious for the number of bugs it can create, and the possibility of complete save file corruption. If you are getting the "LOOKUP FAILED!" bug, you can try these things.

If You Wish to keep Creation Club content ON:
1 - Verify integrity of game files. This should restore any corruped or delete files.
2 - Relaunch the game, and check if your creation club content is present during gameplay.

If you wish to keep Creation Club content OFF:
1 - Navigate to Fallout 4 on the steam app
2 - Right click on the game, hover over "manage" and click "browse local files"
3 - Click on the "Data" Folder
4 - Delete everything that starts with "CC". Anything that starts with "CC" is creation club content. This will delete all creation club content until the game's files are verified (either manually or rarely, Steam may do it if the game is corrupted). Do keep in mind that this may corrupt your files that heavily rely on Creation Club content until the content is reinstalled.
5 - Launch the game, load your save, and check.

Issue #2 - Mods

Mods are also a very popular way to add content to Fallout 4, especially on Xbox and PC. However, mods can be risky, as stated by Bethesda.

If you wish to keep mods ON:
1 - Make sure that all mods you have downloaded are compatible with the latest version of Fallout 4. After the next-gen update, lots of mods have been reported to have compatibility issues. The easy way to do this is to check the descriptions of some mods, or if you downloaded them from Nexus, check when the mod was uploaded.
2 - If that doesn't work, roll back Fallout 4 to the previous version, that way mods will be compatible again. Unfortunately, the next-gen update absolutely destroyed a bunch of load orders, so this may be the only option if you have mods you really want to keep using.

If you wish to turn mods OFF:
1: Use the default mod loader that Bethesda provides in game to uninstall broken mods.
2: If that doesn't work, preform a clean install of Fallout 4, or delete everything from the "Data" folder, and reverify all the files. Be warned, the second option should be done at your own risk.

Issue #3 - "Strings" Folder

The last option you may be able to try, is to delete everything in the "Strings" folder.

Deleting the contents of the "Strings" folder.
1 - Use the same method described in "Issue #1 - Creation Club" to reach the game files page.
2 - Click on "Data"
3 - Click on "Strings"
4 - Copy and paste all the files into a new folder (outside of the Fallout 4 directory) to backup all files
5 - Delete everything in the "Strings" folder (backup highly recommended)

Issue #4 - Clean Install

If none of the other options work for you, you may have to perform a clean install of Fallout 4.

Backing up your save files before you do a clean install:
1 - Go to the "Documents" folder on your computer
2- Find "My Games" and then "Fallout 4"
3 - Find the "Saves Folder"
4 - Copy and paste the folder into a new folder or directory (not associated with anything else)

How to perform a clean install of Fallout 4:
1 - Find the game in your library, and rick click on its icon.
2 - Hover over manage and click "uninstall" and confirm.
3 - Reinstall the game with the obvious blue button where "Play" used to be.
4 - Wait for the game to reinstall.