If disabling plugins and extensions resolves the browser issue that you were encountering, it can be helpful to individual re-enable plugins and extensions, in order to determine which plugin is causing the incompatibility.
Choose Enable for each extension you wish to turn on.
Alternatively, if you wish to disable all extensions as a troubleshooting measure, you may choose to Create a new Mozilla Firefox Profile.
Choose Disable for each extension that you wish to turn off.
From the left navigation pane, choose Extensions.
Choose Always Activate or Ask to Activate for each plugin, as needed.
Alternatively, if you wish to disable all plugins as a troubleshooting measure, you may choose to Create a new Mozilla Firefox Profile.
Choose Never Activate for each plugin that you wish to disable.
From the left navigation pane, choose Plugins.
Click the Firefox menu icon in the upper right of the browser toolbar.
Enable-disable plugins and extensions for Mozilla Firefox Browser plugins To disable plugins