Please check the symptoms of each type of common post update issue and follow the guide best matching :)

If you are using this guide to correct an error that has occurred with a different mod, simply reference that mod's ID number folder in place of the examples below :)



Mod Mismatch Errors, and how to easily fix them.
For Installation mismatches follow the lower guide.

Symptoms
Can't place structures
Engrams can not be learned
Can't see engrams
Missing structures


Cause;
It can occur during the download of an update when an interruption may have occurred and few bits of information went missing between steam's file repository and your server or system.

Or

Files were corrupted during an installation or update due to an interruption.

This happens to a small number of users after any ark mod and sometimes game update, it is unfortunately just bad luck during download that an interruption or a checksum failure occurs, It is something mod makers can't prevent. The effects of a mismatch vary depending on what files are altered or missing.

Steam checks and corrects game files for mismatches automatically, by verifying game cache integrity, however, mods do not get checked in the same way, as steam does not consider them to be part of the core game. This means the mod folder will need to be corrected manually on either the server or the client system using the easy troubleshooting options below.


How to identify if the mismatch is in the server files or the user files;
If one user is having the issue on the server but no one else, the users mod folder 764755314 needs deleting and redownloading (on their personal computer)

If all users are having issues on the server, but it runs fine in singleplayer, the server mod folder 764755314 will need deleting and redownloading. (On the server)


Solution;
Delete mod folder 764755314 and redownload it.
You can find this folder in;
Steam\SteamApps\common\ARK\ShooterGame\Content\Mods
Do this on your system if Singleplayer or the server if Multiplayer.
If you update the server files via FTP using a copy of the mod files on your system, check to make sure your system files are correct by running it in single player first.

Unsubscribing and resubscribing to a mod does not delete and refresh the mod files. Which is why it is important to follow the steps above :)

You may want to rollback to the previous save before the issue, but this depends on the type of mismatch if no parts are missing from your server or game it is not required.



Symtoms
Mod will not install

Cause;
These are rare and occur for the same reason as the mismatches above however this means the mismatch is located in the installer files. This fix requires an extra step to refresh installer files.


Solution

You need to start by unsubbing to the mod. Then close steam and delete mod folder 764755314
You can find this folder in;
Steam\SteamApps\common\ARK\ShooterGame\Content\Mods
Make sure you also delete the ".MOD" in the same directory given above which has the name 764755314
You then need to also to delete the steam cached copy of the mod which is found in the steam directory rather than the game directory,
Steam\steamapps\workshop\content\346110"
deleting mod folder 764755314 from the above directory and also (If present) the ".MOD" file again.
You now need to restart steam, resub to the mod and start the game. This will trigger a clean install.
Note; You may need to start the game twice after this process for the mod install to start, as it will knock the game and steam's mod copies slightly out of sync on the first start up :)



Symtoms
Structures missing from single player game after an update


Cause
If you are playing single player there is an unfortunate occurrence that could happen if when you click launch game the mod update is still installing (displayed in the bottom right of screen) it will launch the game without the mod installed yet.
When the game loads up, as the mod is not installed, the mod items are not loaded, then when you exit, an auto save occurs with the parts not there (this is easily fixable so don't panic)

Solution
If you restore to the save file before the issue it will be corrected. Use this guide to restore an ark save file, If you are restoring a singleplayer save, you can skip step one, "log into control panel" and instead go straight to your saved game folder in your ark directory.

The saved game folder for ark is located here;
Steam\SteamApps\common\ARK\ShooterGame\Saved

Restore Save File Guide;
https://serverblend.com/my/knowledgebase/74/Reverting-to-a-previous-ARKSurvival-Evolved-save.html



:)