Opening the "Add-ons Manager" shows a message "You don't have any add-ons of this type installed" despite the fact I have many add-ons installed. In fact, I can still use add-ons just fine, they just don't show up in the manager. So, I can't access preferences for most of my add-ons.
I had this problem once before and was able to solve it through extensive Google searching. However, when I fixed the problem before, I had to re-add all of my add-ons to the browser window as it was reset to the default in fixing it. My issue isn't so much how to fix it like I did before, but rather—since it seems to have been only a temporary fix—figure out how to prevent it from happening again. See, I really don't want to have to do what I did before as it is time consuming. Especially, if it's going to happen again. Like, I don't want to have to reset and re-organize Firefox every couple of months.
The solution I used before, if I recall correctly, was deleting some preference files, re-opening Firefox, and then putting everything back the way it was. Restarting Firefox in safe mode did nothing and restarting my computer did nothing. I can't remember if I updated Firefox after noticing the problem the first time; I don't think I did, so I'm not sure if it would've fixed the problem or not (or if updating caused it because I had recently updated Firefox prior to noticing the problem).
One more piece of info is that the first time this happened to me was Firefox 14 or 14.1 (or .0.1 maybe).
Add-ons Manager click the Extension to See your Installed Addons.
How you installed firefox Add-ons Directly from the firefox addon website or installed as a file from local disk.
I installed them from the Firefox add-on website. The problem is when I click Add-ons Manager > Extensions, I get "You don't have any add-ons of this type installed" despite having a bunch installed and usable.
It is possible that there is a problem with the file(s) that store the extensions registry.
Delete the files extensions.* (e.g. extensions.sqlite, extensions.ini, extensions.cache) and compatibility.ini in the Firefox profile folder to reset the extensions registry.
New files will be created when required.
See "Corrupt extension files":
If you see disabled, not compatible, extensions in "Tools > Add-ons > Extensions" then click the Tools button at the left side of the Search Bar (or click the "Find Updates" button in older Firefox versions) to check if there is a compatibility update available.
If this hasn't helped then also try to delete the addons.sqlite file.
Right, I've done that before to fix the problem but fixing it reset the icons on my browser window to the default. Plus (and I actually just remembered this), I had to reinstall every single one of my add-ons after deleting those files last time. I guess what I'm wondering is—since this has happened multiple times—if there is a way to fix it without having to reorganize and reinstall everything again?
I had this exact problem a couple of days ago. The workaround was rather easy:
Just go to the add-ons-manager and install some random add-on from addons.mozilla.org. Once you restart Firefox, all the add-ons are back in the add-ons-manager, but they are disabled. Just enable them all, and you're back to normal.
All the settings, icons, etc., of the different add-ons are still there.
Tried that, still doesn't come up---got the new add-on I just installed, but the add on page is still blank?
Holy Cow! I was just playing around on the add-ons page that wouldn't come up----I might there are two buttons, "my add-ons" and "available add-ons"----neither of them work Soooooo, I typed "my add-ons" in the SEARCH box, and all my add-ons came up as they were supposed to!
Gosh, FF, you're driving me nuts!
Rut-Roh------Further, I just installed another add on and now when I go to "my add-ons", ONLY THIS NEW ADD ON SHOWS UP, none of the others??????