I am using scoped_lock with interprocess_mutex. I suspect that I have one of my threads trying to lock the mutex multiple times before it is unlocked. Is there a way to check and see if a mutex has already been locked by the current thread? _________________________________________________________________ Windows 7: Unclutter your desktop. Learn more. http://www.microsoft.com/windows/windows-7/videos-tours.aspx?h=7sec&slideid=1&media=aero-shake-7second&listid=1&stop=1&ocid=PID24727::T:WLMTAGL:ON:WL:en-US:WWL_WIN_7secdemo:122009