How to overcome data loss on Mac OS?

Question

Hard disks

The computer after turning off or rebooting loses the changes made to it. (Rolls back to the last time when data was not lost after shutdown)
If you turn it on, create a file and turn it off in a short period of time, then everything is fine.
The loss manifests itself if turned off after a long use (starting from several hours).
The last time before shutting down, I noticed that free memory had run out (0kb - free), despite the fact that out of 2tb only 300gb was occupied

Answer 1

Solution: Reinstall Mac OS and disable auto-updates

Answer 2

Dead hard drive/ssd? Check the smart and the status of the drive/drives.