As time has gone by, we have been able to see how the extensions that we usually install in our browsers, have been gaining in importance, becoming key elements in some cases for the proper functioning of the software.
Well, it is possible that a few hours in this part some have encountered the problem that suddenly all the extensions of Firefox, the proposal of this type in Mozilla, are disabled for no apparent reason, or at least the majority. In this case, it is most likely that they show messages that indicate that they cannot verify their use in Firefox and therefore have been deactivated, all in the browser's complement manager, which can be somewhat worrisome.
There are many extensions affected by this new bug that has just been discovered, some of which are as well known and used as LastPass, Ghostery, Download Manager, Dark Mode, NoScript, etc. That is why if you are facing this problem, the option that the browser proposes to us so that everything returns to normal, is to eliminate these small added programs and look for a substitute, which represents a serious inconvenience in some cases.
In fact, many might think that this is due to the change in extension policies that Mozilla has announced that it will apply in the future, but no, it has nothing to do with all this, at least for the moment.
How to fix the failure of Firefox extensions
We will say that all this is due to an error related to the signature of the extensions themselves since all these affected extensions are suddenly disabled due to the expiration of the signature certificate. In fact, all of them must be signed from Firefox 48 and Firefox ESR 52 so the browser will block the installation of extensions with invalid certificates. Or without certificates, and that is what is now causing the problems that we have done to you mention.
At the same time, it is also being reported that some users cannot install extensions from the official Mozilla add-ons repository. Therefore, those who have installed a Nightly or Dev version of Firefox, can disable the extension signature, some claim that this solved the problem temporarily. For this it is necessary to access the preference "xpinstall.signatures.required" and set it to "false" in "about: config".
This is to disable the signature, but we can also change the date of the system to the previous day to resolve it temporarily, but that can lead to other problems. Therefore, at this time this is a failure that can only be resolved by Mozilla since the company needs to renew the certificate or create a new one to solve the problem.
This is why we do not recommend removing the affected extensions and waiting for Mozilla to resolve them as soon as possible, which would solve all this automatically.