Do you use CCleaner?

Yes I do use CCleaner and I have recently used it. Rgds Eric

Have a look at this thread: https://support.mozilla.org/en-US/questions/1163972

Have read the thread. It seems that CCleaner may be the problem but does not give a solution. What do you suggest I do the recover my files in addition to ditching CCleaner.

Rgds Eric

I suggest you go the the CCleaner forum with all the other HAPPY customers and read that discussion for fixes. CCleaner broke it and needs to provide you the solution. Most fixes I have seen so far involve using backups. You could try that.