It seems I managed to find a workaround (and possible the problem place; now it works for me -- after several reboots the problem doesn't appear anymore): need just to disable 'checkfs.sh' script run on startup (mv /etc/rcS.d/S30checkfs.sh /etc/rcS.d/K30checkfs.sh -- according to the documentation in /etc/rcS.d/README).
Somebody, who is responsible for that subsystem in Ubuntu, please, investigate this issue: it is a really serious and annoying bug, which has already corrupted some files on my PC.
It seems I managed to find a workaround (and possible the problem place; now it works for me -- after several reboots the problem doesn't appear anymore): need just to disable 'checkfs.sh' script run on startup (mv /etc/rcS. d/S30checkfs. sh /etc/rcS. d/K30checkfs. sh -- according to the documentation in /etc/rcS.d/README).
Somebody, who is responsible for that subsystem in Ubuntu, please, investigate this issue: it is a really serious and annoying bug, which has already corrupted some files on my PC.
Thank you