Did you played 7 years at one session ? :-) I think normaly the permabackup get generated when you exit the game.
When you see at your log
Exception while init loading file: C:/Users/Admin/AppData/LocalLow/Ludeon Studios/RimWorld by Ludeon Studios\Saves\Liptacze (permanentna śmierć).rws
System.Xml.XmlException: '.', hexadecimal value 0x00, is an invalid character. Line 89897, position 1.
that indicate that Rimworld couldn't load the safegame completly.
When you have other messages, it can be a mod issue. But mod issues that prevent to load a safegame are mosttimes similar deadly to your colony.
If you used steam workshop, it could be that a mod got update recently, and the new mod version cause the issue, then a rollback to an older mod version could help, or ask the mod author.
Other mod conflicts are impossible to detect/fix for regular player, that's why it is a bad idea to do permadeath with antested modlist. At last no error's should show at the log after you start rimworld.
