Well usual crashes are caused by out dated video card drivers or corrupted ones so can update them. The next is your running a unsupported browser. Note : Firefox 57.0 is the current release https://www.mozilla.org/firefox/all/ Full Version Installer Note : Legacy Extensions will be disabled and or removed. If stick the above in check this ASAP : Go to the Firefox 3 Bar Menu --> Help ? --> Troubleshooting Information Page and take a look in the Accessibility section if accessibility is set to "true" there. if yes, go to the Firefox 3 Bar Menu --> Options --> Privacy & Security panel and under Permissions check the setting to Prevent Accessibility Services from accessing your browser. Alternatively : 52.5.0 ESR is secure. It will continue to get security updates until May 2018, and you can download and install it from this page: https://www.mozilla.org/en-US/firefox/organizations/all/ <b>Note : Legacy Extensions will be deleted or removed in any version update after May 2018</b>. You should make a backup of your Profile before going back and just because: https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles Please let us know if this solved your issue or if need further assistance.