Much like the Windows Update Errors I mentioned previously, it seems that Firefox has similar problems. Unlike those from Windows Update, however, these at least return a somewhat-friendly message, which helps a bit.
So instead of getting a cryptic hex number, you are given a message that reads something like “an error occurred while trying to find updates”. Unfortunately, there isn’t much help in resolving this error – and because many updates come from individual users, rather than a central repository – you may be stuck.
While there isn’t much you can do if you get such an error as a user, there is at least the possibility that you can do some troubleshooting if you are a developer – or if you want to do some digging on behalf of the developer and send them some information.
The Firefox (and generally, the entire Mozilla) update process requires a few pieces to be in place in order to work correctly. One of the simplest issues is that the connection is not working right over SSL. However, this is almost impossible to troubleshoot, so about all you can do is try again to see if it works. If not, assume it isn’t the issue and move on, because you can’t help, even if it is the problem.
More likely is that if, like me, you forgot to update the MaxVersion setting in the update.rdf file, it won’t work correctly. That is something I have done – more than once. Another item that could be at fault is if the UpdateKey and the Signature do not match. In that case, the update process will fail.
Luckily for most developers, if you host your addon at mozilla.org, many of these items are handled for you, and keeping some of the items updated (like the MaxVersion) are trivial. So it is something to look at – and although it does require jumping through some hoops, it may be worth the effort.