Symptoms:
- Can't place structures
- Missing structures
- Engrams can not be learned
- Can't see engrams
- Crafting Table is missing items or items in the table can't be crafted (try picking up the table and placing it again before trying anything else)

If you experience these symptoms, you have a corrupted mod install on either your computer or the server you play on.

BEFORE FOLLOWING THE STEPS BELOW:
- Check to see if your server is using the “automanagedmods” launch parameter. Apparently this can cause some of the above symptoms if it isn't working correctly.
- Try moving the problematic mod to first in the load order. If this fixes your issue, it's possible that one of the other mods is the corrupted mod, and is breaking mods that load after it. Check each mod that was loading before the problematic mod.
- When following the instructions below, if a modder has failed to post the Mod ID on their mod's Steam page, it is simply the number at the end of the address bar on the mod's Steam page.
- In the case of Arkitect Structures: Atlas, if Atlas structures are missing, the corruption could be in the Core mod, the Atlas mod, or both. Atlas relies on files in the Core mod, so if the follow procedure doesn't work for you, follow the same steps for the Core mod too.

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How to determine which computer has the corrupt files:

If one user is having the issue on the server but no one else is, the user needs to follow the client reinstall instructions below (on their personal computer).

If all users are having issues on the server, but it runs fine in single-player, the mod will need to be reinstalled on the server.

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How to completely reinstall a mod (client and singleplayer):
1. Close Steam completely.
2. Go to the mod's steam page and unsubscribe.
3. On your computer go to ...\Steam\steamapps\common\ARK\ShooterGame\Content\Mods and remove the folder and file named modID, then ...\Steam\steamapps\workshop\content\346110\ and remove the folder.
4. Open Steam
5. Clear Steam cache: click View (on top) -> Settings -> Downloads -> Press Clear download cache button at the bottom
6. Return to the mod's Steam page and subscribe
7. If missing structures was one of your symptoms, restore a backup of your save file.
8. Open Steam, wait for the mod to finish downloading, run Ark and let it install (watch bottom right corner).

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How to completely reinstall a mod (server):
Very similar to the client instructions with some variation.
1. Whether you self-host or rent a server, you will want to shut down your server, then go to <server install folder>\ShooterGame\Content\Mods and delete the mod's folder and matching .mod file.
2a. If you self-host, find your workshop cache and delete it. The common location is SteamCMD\steamapps\workshop\content.
2b. If you rent a server, you will likely not have control over the mod cache, and there is a chance the host's cache of the mod is corrupt, which means when your server reinstalls the update it will just reinstall the corrupted files again. You can talk to the host's support to get them to clear their cache or at least that specific mod. Alternatively, if you are able to FTP into your server, you can FTP a known-good copy of the mod files to the server, bypassing the host's update system. Be sure to copy the mod folder and the matching .mod file. Filezilla Client is a popular program used for FTP.
3. Re-download/reinstall the mod on your server.
4. If missing structures was one of your symptoms, restore a backup of your save file.
5. Once you have completed these steps you can start your server again.