hi Zeren, in consumer facing firefox release and beta versions the addon signing requirement will be enforced. the workaround will be to use firefox developer edition where you will be able to switch off addon signing by setting xpinstall.signatures.required to false: https://www.mozilla.org/firefox/developer/

Add-on signing in Firefox

After changing the setting to false and restarting my browser, my addons are still disabled with the alert telling me they are not signed. Is there another step to this?

a warning will still show up, but the extensions should no longer be disabled after you've done this.

That doesn't seem to be the case. They are all disabled and I cannot access them.

since it looks like this is affecting all addons - even signed ones - maybe the files in your profile folder that store the information about your extensions might have become corrupted. please go to the firefox menu ≡ > help ? > troubleshooting information > profile - show folder... then windows explorer should open up your profile folder. in there look for the files named extensions.ini, extensions.sqlite, extensions.sqlite-journal (and in some cases also extensions.txt, extensions.rdf). delete or rename those files and quit firefox, they will be regenerated the next time you launch firefox.

also see Corrupt extension files

Thank you! That fixed all of my issues!