Have you tried refreshing or reinstalling Firefox? If none of these work, then this issue may be caused by adware or malware. If adware/malware is the cause of the problem, these articles may help: [[Troubleshoot Firefox issues caused by malware]] [[Troubleshoot Firefox crashes (closing or quitting unexpectedly)]] Run the malware scanning programs listed in the first link. Try running all of them because each program detects different malware. You can also start Firefox in Troubleshoot Mode to see if the problem still occurs. [[Diagnose Firefox issues using Troubleshoot Mode]]