Product Firefox Release Channel release Version 50.0.2 Build ID 20161129173726 OS Windows 10 OS Version 10.0.14393 Signature: shutdownhang | ntdll.dll@0x6dd3c iimFirefoxConnector.dll = iMacros combase.dll = Microsoft KERNELBASE.dll = Microsoft ntdll.dll = Microsoft This is for Sumo's Related Bugs 1257058 NEW --- shutdown crash after failed imap login attempt with no password. shutdownhang | WaitForSingleObjectEx | WaitForSingleObject | _PR_MD_WAIT_CV | _PR_WaitCondVar | PR_WaitCondVar | mozilla::CondVar::Wait | nsEventQueue::GetEvent ------------------ '''Disable iMacros''' Perform a System File Check to fix corrupted system files Win 7, 8, 10, Vista: https://support.microsoft.com/en-us/kb/929833 Win XP: https://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/system_file_checker.mspx?mfr=true See if there are updates for your graphics drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration