Enabled add-ons are missing
I'm away at another location for a few months out of the year. The computer in the other location is almost identical to this one, done in a very simple manner, by using a backup and then reinstalling everything from previous computer to current, most of which is data.
The Firefox profile is copied over and then the version of the program from that other computer is copied, so the profile and program match. The last step is to disable each add-on individually, then to immediately enable them again. (Otherwise, the browser won't connect to the internet.)
I followed the same procedure today as every single time. But then I noticed the blank new tab add-on isn't working. And upon looking at the add-ons...none of the enabled ones are listed (or working). Only the disabled and recommended ones. I don't even know which were installed, and would have a hell of a time figuring out which ones are supposed to be there, and how they're set up.
Where did they go, and how can they be reinstated?
This has never happened before, and I've been doing this same thing for at least 3 years.
Thanks in advance.