Why does Unity rebuild the library after resetting a PC?

Asset & Content Management
1

Due to a GPU problem my PC won’t come out of sleep properly (or at least the display won’t receive any signal) so I have to reset it. This has happened twice now and both times the Unity editor may have been open when I put the PC into sleep mode.

After rebooting the PC and reloading the Unity project, it started to rebuild the library. In Unity versions before 5.5 that also causes prefabs to break.

What would cause Unity to rebuild the project library after resetting the PC? File corruption?

I have tried to simulate a reset by closing the process through Task Manager, but that doesn’t trigger a rebuild. At this time I don’t feel like resetting my PC for the sake of experimentation though.

The project is stored on a Samsung 850 Pro SSD. Windows is installed on another disk, a Samsung 830 Pro SSD. SMART doesn’t report any malfunctions, but CHKDSK did trigger eventually on the project disk.

CHKDSK discovered free space marked as allocated in the master file table (MFT) bitmap.
CHKDSK discovered free space marked as allocated in the volume bitmap.
Windows has made corrections to the file system.

2

Well it seems that Windows might have modified the project SSD enough for Unity to trigger a re-import.

I’d recommend fixing your “GPU problem”, which is the original cause of the issue. After all, having a fully-functional GPU is really nice.

3

Of course. However we’re talking Nvidia drivers. Just uninstalled all old driver leftovers with ddu, updated the GPU bios and reinstalled the latest drivers.

Still, I’m more concerned about the SSD. Would be bad if the hardware doesn’t report data corruption. That would also make me question the data integrity of my backups. I’d feel better if Unity rebuilding the library after resetting the PC is just a software issue.