It has been reported that sometimes on some machines Firefox crashes due to the Flash Player plugin's protected mode feature. You can disable this feature by following the instructions provided by Adobe.
If this doesn't help you, there are several possible issues that could cause Firefox to crash that you should consider:
- Update Firefox
- Update your plugins
- Update your graphics card driver
- Turn off hardware acceleration
If you are still experiencing the same problem, then you can try to take a closer look at the add-ons and extensions that you have installed in Firefox. In order to determine what is causing Firefox to crash you should run the program in safe mode. To do that, press the Menu button, click Help and select Restart with Add-ons Disabled. Next, you should check for faulty extensions by enabling them one at a time. Repeat the procedure until you determine what is causing Firefox to crash, then remove the plug-in as necessary.
More information can be found by accessing the link below:
https://support.mozilla.org/en-US/products/firefox/fix-problems