You are right. Nothing is sure.
I was not aware activity monitor was able to record something I can share.
Not sure if the DB is corrupted or not.
But in this case I was unable to use Devonthing menues because of black screen then transparent windows with no menu etc.
With this problem I discover some thread about backup and sequential backup. Arq 7 seems fine. Will test it and buy it.
It seems easy to backup all my databases but really it is painful to find where and what are others files to backup to not lose some plist and others files. Will search in my previous backup.
Any advice appreciated.