[SOLVED] FNIS Error(5) Invalid Class

[Dorabella]

As per title, FNIS reports invalid class error . Never happened before . Thinking I had messed something up, I uninstalled Skyrim , cleaning up any remaining folders . I reinstalled , but the error persists .
I took a look at the various threads about the problem , and , the solutions presented , had no effect

 

Spoiler

 

Edited November 29, 2024 by Dorabella
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[Kastagir]

According to the FNIS mod page all error codes below 2000 are reported by Windows.  Your installation isn't under \Program Files so UAC likely isn't an issue.  Have you verified that you have exceptions set up in your AV software (e.g. Windows Defender)?  It's possible an automatic software update reset your exceptions.  Also, you could try uninstalling FNIS in NMM and install it manually.

 

Sudden changes like this that result in a Windows-related error (as Error 5 is according to the author of FNIS) suggest this was caused by an update to Windows or one of its components and not a mod.

Edited November 29, 2024 by Kastagir

[Dorabella]

The strange thing is that , until yesterday, it was working properly . Windows, made an update 

If the update was to blame, would a restore , remove the update? Still if so, is it possible to block automatic Windows updates?

 

21 minutes ago, Kastagir said:

Your installation isn't under \Program Files

As you can see in the screen , the installation path, it has been there for years

[Kastagir]

First I would try to verify that GenerateFNISforUsers.exe is included in your AV exceptions list - or that your entire Skryim game folder path is.  You could also try stopping the AV service temporarily while you run FNIS.  Finally, I would check UAC settings in the event MS extended UAC protection to the entire C:\ drive.  Up until now UAC has protected C:\Program Files and C:\Windows and I don't see anything suggesting that has changed.  I moved my steam library to another drive for performance benefits long ago so any change to UAC affecting the C:\ drive wouldn't affect me.  Windows Update frequently includes updates to Windows Defender and these could reset your exceptions.

 

If none of this helps you could try removing the update through System Restore but if you have uninstalled and reinstalled Skyrim that restore point may be gone.

[Dorabella]

2 hours ago, Kastagir said:

Windows Update frequently includes updates to Windows Defender and these could reset your exceptions.

I did a Windows reset to a few days before the update . FNIS , it's back to work

 

Damn updates . Thank's

[renferal]

I opened another thread about this and I'm cross posting my solution here just in case someone finds it over mine.
 

I found a more user-friendly version, for anyone running into this issue in the future. I followed the guides outlined here in this walkthrough:
https://kb.sambapos.com/en/11-5-how-to-resolve-invalid-class-error/

The above link is not a walkthrough specifically for FNIS, mind you, just another company who has run into the same problem. Their solution was a bit easier for me than trusting a bat file.
 

I followed Method 2 of that link and it started working again. In case that link gets taken down, the steps are this:

 

1. Enter Windows Start > Services > Services Application > Windows Management Instrumentation service. Stop the service.

2. Navigate to C:\Windows\system32\wbem\. Find the repository folder. Rename that folder to repository_old. (This backs up the folder, and a new one will be generated when you start the service again. You can actually use this method with a lot of files when modding Skyrim, too  )

3. Go back to Services and Start the Windows Management Instrumentation again. This should generate a new repository folder.

That's all it took to get me back up and running again! There's further methods on that link others can try if that doesn't work. The core problem seems to be the same. Invalid Class seems to be indicative of a WMI corruption, or a not running WMI service.

Edited May 5, 2025 by renferal