Disable Firefox startup plugins check
Perhaps some coding mistakes or a crazy brain over there at Firefox resulted to this nightmare, Firefox always opening upon startup a tab for plugin update checking, an update that most of the time won’t even occur because of some real or supposed error.
I thought that using a plugin called Disable Add-On Compatibility Checks, would solve the problem, and it did, for a few days — then the nightmare began again…
You can try the plugin, in case it works on your version of Firefox, but in my case the only thing that worked –so far– was to enter in Firefox advanced settings…
In the address bar write: about:config
At the filter bar search for blocklist and make these changes:
turn “extensions.blocklist.enabled” into false
modify “extensions.blocklist.url” and delete the url
modify “extensions.blocklist.itemURL” and delete the url
modify “extensions.blocklist.detailsURL” and delete the url
If you make these changes you will be able to update your plugins only manually, by opening the Add-Ons tab yourself, going to “Plugins” and clicking on “Check for updates…” at the top of the list.