So the defrag was a failure. The harddrive with the missing data did not defrag. All it did was "consolidate" and it only did it for like 5 minutes. My main drive did defrag i think. there was no visual so i dont know if it was actually doing anything. the situation is unchanged. sadly.
So, files that disappear; Where do they go? Are they deleted, moved, hidden? Do they all stay together or do they get scattered?