Bug#826426: source of the problem found!

I had installed software from picotech: https://www.picotech.com/ When I removed picotech software with aptitude, the problem disappeared.

Bug#826426: keepass2 won't start, problem in mono

Package: keepass2 Version: 2.28+dfsg-1 Severity: grave Justification: renders package unusable Dear Maintainer, I *guess* the problem is in updated mono. I tested keepass2 on a fresh user account, but the problem persisted. So I think it is not configuration issue. Then I tried re-installing