User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:20.0) Gecko/20100101 Firefox/20.0 Build ID: 20130326150557 Steps to reproduce: Closed Firefox and then opened it up. This is also happening on another computer in my house. Actual results: Received an error that previous sessions could not be opened Expected results: The previous sessions should have closed when Firefox was closed.

Thanks for reporting this. This is the same problem reported by other users. You can read about it in the Support Forum https://support.mozilla.org/en-US/questions/955603?esab=a&s=embarrassing&r=0&as=s I think this bug is a duplicate of https://bugzilla.mozilla.org/show_bug.cgi?id=845681