This can be caused if one of the files that stores details of installed extensions is corrupt.

1. Open your profile folder, for details of how to find it see https://support.mozilla.com/kb/Profiles
2. Close Firefox
3. Delete the following files if they exist, extensions.cache, extensions.rdf, extensions.ini and extensions.sqlite
4. Re-start Firefox, it will then rebuild the list on installed extensions

Hi TonyE,

Thank you very much for taking a look at my problem. I appreciate it! The steps you posted look good to me. However, I got the same result. My profile folder was located in C:\Users\(_myusername_)\AppData\Roaming\Mozilla\Firefox\Profiles\sg3nxpk4.default . The files you listed were all there, as well as one additional one called extensions.log, which I tried deleting as well after trying the first 4. Everything was as you described; Firefox did recreate the files, but the Add-ons Manager continues to come up blank.

thanks again,

-fishtacos123

TonyE,

EDIT: All of my extensions (in the browser) are gone. So something worked!

-fishtacos123

You seem to have been using this profile with quite a few Firefox test version according the the presence of many extensions.checkCompatibility.* prefs in your More system details list.

Maybe you should create a new profile as a test to check if your current profile is causing the problems.

See:

• Basic Troubleshooting: Make a new profile

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If that new profile works then you can transfer some files from the old profile to that new profile (be careful not to copy corrupted files)

See:

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Hey cor-el,

The very first step of creating a new profile was to back up the current one. Well, guess what? The current profile folder refused to copy. By copying the internal files that would actually cooperate, one file was left...and it was corrupted. Now all of my extensions are back, and they are visible in the all-too-cool Add-ons Manager!

Thank you so much,

fishtacos123

You're welcome

Which file was causing the problem?

how do I create a new profile ?? where are the profiles stored in the program ?? when I bring up the addons manager in a new tab...there is no extensions listed..but they are all working..help please...I also read something about deleting 3 files in my profile to fix the problem..what 3 files and where do I go to do this ??where is my profile stored ??

You can use this button to go to the Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Open Containing Folder

• http://kb.mozillazine.org/Profile_folder_-_Firefox

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.

• https://support.mozilla.org/kb/Profiles

New files will be created when required.

See "Corrupt extension files":

• http://kb.mozillazine.org/Unable_to_install_themes_or_extensions
• https://support.mozilla.org/kb/Unable+to+install+add-ons

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.

I found the profile but within that folder under the name extensions..this is what I found extensions(config files) extensions(text doc) extensions.rdf extensions.sqlite extensions.sqlite-journal and then of course there is the entire file of extentions... but there was just one of the files that you mentioned to me(extensions.sqlite, extensions.ini, extensions.cache)

I fixed it..remember I told you that I could just find one of those files...the extensions.sqlite...so I deleted that one file and there you go....all is well again..everything returned....I guess just the one file was corupted.....its fixed thank you very much !!!

You're welcome.

Not all files need to be there, so you can skip files that aren't present on your computer.