Recently I received a customer’s complaint that adobe flash player causes Firefox freezing and sometimes crash. The symptom is that whatever website opened with Firefox, no matter whether there’s any flash content, the browser will freeze for 1-2 minutes and it happens every 3-5 minutes in intervals. And if you disabled flash player plugin, no freezing anymore and everything becomes fine.
We have tried reinstalling both Firefox and flash player, rolling back to previous versions and disabling flash player hardware acceleration, all cannot help. BTW, the display card is Mobile Intel(R) 4 Series Express Chipset Family. And the freezing only happens to Firefox, not to IE.
Finally, we found one solution for it which solved the problem. That is creating a brand new user account. When you switch to another user account, the stored local data was clear and Firefox can load add-ons successfully, so no more freezing.
Reference bug link: https://bugbase.adobe.com/index.cfm?event=bug&id=2968849
Ru Wan, QE Dev Intern in Flash Runtime Customer Experience China Team