After migrating from another PC, I installed all packages (including nvidia drivers). Since my new PC doesn't have an nvidia card, only HD4000, I removed the nvidia with "apt-get purge nvidia*". Then I had this problem. Same errors in .xsession-errors.
"gsettings reset org.compiz.core:/org/compiz/profiles/unity/plugins/core/ active-plugins" has fixed it for now.
TL;DR removing nvidia drivers can cause this problem. Should reset compiz after remove.
After migrating from another PC, I installed all packages (including nvidia drivers). Since my new PC doesn't have an nvidia card, only HD4000, I removed the nvidia with "apt-get purge nvidia*". Then I had this problem. Same errors in .xsession-errors.
"gsettings reset org.compiz. core:/org/ compiz/ profiles/ unity/plugins/ core/ active-plugins" has fixed it for now.
TL;DR removing nvidia drivers can cause this problem. Should reset compiz after remove.