FCPX will not export - cannot cancel previous project in share monitor

FCPX is absolutely locked and blocked with a project stuck in my Share Monitor - it has been cancelling it for 5 hours to no avail. As a result nothing will export, not even going to compressor - everything waits for the "cancelled file" to cancel which it will not do. Any help is welcome - I have shut down, rebooted countless times - at the point of wiping the program as it has become entirely useless.
grateful for ANY suggestions
Scott