Game no longer detects my prefab in A21.1 plus my files were deleted

[FranticDan]

On Sunday, I was using A21.1 to edit my prefab, in 2 player. We worked about 7 hours. My prefab uses custom blocks, items and entities etc, so I have various files in the Mods folder in the main directory.
Then Tuesday, I loaded up the game and got a bunch of errors. I panicked and was very confused. I noticed that the prefab that got loaded was a version of my prefab from a few years ago (A19 version), but more shockingly, almost all of my mod folders/files were deleted. The only files that were spared was 4 of my prefab files, and the worlds folder was intact.

I have absolutely no idea what could have caused files to be deleted. I restored the files that were deleted, which I had saved in a ZIP before the Sunday work, including the 4 prefab files that were last edited last year, the 4 surviving prefab files had Sunday's date on them, so no progress was lost thankfully.

A21.1 no longer detects my prefab at all, so I've had to revert back in A21.0

After about 6 hours work on Tuesday, I went to make a backup due to the trauma, and noticed right away that the same 4 prefab files were deleted again, but everything else was intact.


In the attached photos, I've highlighted the deleted folders/files

 

[Jugginator]

What's the error in the log file?

 

[FranticDan]

What's the error in the log file?

Due to actually playing a vanilla survival world in A21.1 after editing (before I discovered deleted files) I don't have a log for the edit session?
I also noticed about 12 hours after posting this, that files were deleted again (folders remained this time) and it happened while I was in the game making edits to the prefab. I know this, because I zipped my mods folder BEFORE exiting to main menu, and didn't realise files were deleted until I tried making edits again 12 hours after I posted this.
Only 4 files for the prefab itself were intact (thankfully!).
Which again, I played vanilla survival between prefab edit sessions before noticing.

I'll be keeping an eye on this going forward, however, I am staying away from A21.1 with prefab editor in the mean time, since that is when this started happening.

I will post a log file next time it happens


I will say this, while editing, it feels like my mouse is active on the desktop, occasionally my game controls will stop responding and I have to Alt+Tab to get controls back, sometimes my display settings will popup over the game (and other types of windows I can't remember), my PC makes error noises. Even my icons on desktop somehow became large size.
None of this happens outside of prefab editor.