All extensions vanished from Add-ons Manager, but some (not all) still work anyway.
Okay, so this all started after I performed a System Restore on Windows 10, due to an unrelated problem. When I came back into Firefox, everything looked okay at first. But then, the problems started popping up.
First I noticed that I couldn't use the "Restore Previous Session" function. Thought that might be due to the Restore I did, but I've restarted FF several times, and I still can't do it. Next, I saw the downloads list said "No downloads for this session", which not only wasn't true then, but after downloading some things, it still said the same. When I Right-Clicked on an image, the menu came up with a bunch of extra options that had never been there before. But only the first time. I right-clicked again, and the menu was normal. Another thing was, the Firefox about:customizing page just loads as a blank page. I did some more checking around, and found that when I went to Firefox about:addons and clicked the Extensions tab, there were none listed. There should have been at least three there: AdBlock Plus, Tineye Reverse Image Search, and Download Flash and Video. I did a search for them, and clicked the buttons to add them to Firefox, but they ended up in the Extensions tab where it said "Downloading" and had a progress bar, but it wasn't doing it. Clicking the X to stop it did nothing. Furthermore, when I tried to use the Tineye and Download Flash and Video extensions, they still worked fine, but AdBlock hasn't been working at all.
Solution choisie
Using System Restore can cause your Firefox installation to get corrupted because only white-listed files are restored, so always be cautious with using System Restore.
- You may lose data in the Firefox profile folder like .js and .ini files
- You may need to reinstall affected software
It is possible that there is a problem with files in the profile folder that store the extensions registry.
Delete the extensions.* files (e.g. extensions.json, extensions.ini, extensions.sqlite) and compatibility.ini in the Firefox profile folder to reset the extensions registry.
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 or not compatible extensions in "3-bar Menu button/Tools > Add-ons > Extensions" then click the Tools button at the left end of the Search bar to check if there is a compatibility update available.
If this didn't help then delete Add-ons.json and possibly prefs.js in case there is a problem with preferences.
You can use this button to go to the current Firefox profile folder:
- Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
- http://kb.mozillazine.org/Profile_folder_-_Firefox
You may have to create a new profile if the current profile is corrupted.
Create a new profile as a test to check if your current profile is causing the problem.
See "Creating a profile":
- https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
- http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues
If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.
You can copy files like these to the current Firefox profile folder to recover specific data.
- bookmarks and history: places.sqlite
- bookmark backups: JSON backups in the bookmarkbackups folder
- SQLite files like cookies.sqlite (cookies) and formhistory.sqlite (saved form data)
- logins.json and key3.db (decryption key) for Passwords saved in the Password Manager
- cert8.db and possibly cert_override.txt for (intermediate) certificates stored in the Certificate Manager
- persdict.dat for words you added to the spelling checker dictionary
- permissions.sqlite for Permissions and possibly content-prefs.sqlite for other Site Preferences
- sessionstore.js for open tabs and pinned tabs and tab groups
Toutes les réponses (3)
Solution choisie
Using System Restore can cause your Firefox installation to get corrupted because only white-listed files are restored, so always be cautious with using System Restore.
- You may lose data in the Firefox profile folder like .js and .ini files
- You may need to reinstall affected software
It is possible that there is a problem with files in the profile folder that store the extensions registry.
Delete the extensions.* files (e.g. extensions.json, extensions.ini, extensions.sqlite) and compatibility.ini in the Firefox profile folder to reset the extensions registry.
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 or not compatible extensions in "3-bar Menu button/Tools > Add-ons > Extensions" then click the Tools button at the left end of the Search bar to check if there is a compatibility update available.
If this didn't help then delete Add-ons.json and possibly prefs.js in case there is a problem with preferences.
You can use this button to go to the current Firefox profile folder:
- Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
- http://kb.mozillazine.org/Profile_folder_-_Firefox
You may have to create a new profile if the current profile is corrupted.
Create a new profile as a test to check if your current profile is causing the problem.
See "Creating a profile":
- https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
- http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues
If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.
You can copy files like these to the current Firefox profile folder to recover specific data.
- bookmarks and history: places.sqlite
- bookmark backups: JSON backups in the bookmarkbackups folder
- SQLite files like cookies.sqlite (cookies) and formhistory.sqlite (saved form data)
- logins.json and key3.db (decryption key) for Passwords saved in the Password Manager
- cert8.db and possibly cert_override.txt for (intermediate) certificates stored in the Certificate Manager
- persdict.dat for words you added to the spelling checker dictionary
- permissions.sqlite for Permissions and possibly content-prefs.sqlite for other Site Preferences
- sessionstore.js for open tabs and pinned tabs and tab groups
Separate Issue; Your System Details shows;
Installed Plug-ins
Shockwave Flash 20.0 r0
Shockwave Flash 15.0 r0
Having more than one version of a program may cause issues.
You must remove the older programs. Then get the current full installer.
Flash: Grab the uninstaller from here: Uninstall Flash Player | Windows Uninstall Flash Player | Mac
Then reinstall the latest version.
Flash Player Version Version: 20.0.0.306
https://www.adobe.com/products/flashplayer/distribution3.html
Note: Windows users should download the ‘’’active_x’’’ for “Internet Explorer,”
and the ‘’’plugin’’’ for “Plugin-based browsers” (like Firefox).
Note: Windows 8 and Windows 10 have built in flash players and Adobe will cause a conflict. Install the ’’’plugin’’’ only. Not the ’’’active_x’’’.
Adobe still offers Flash 18.0.0.326 as its extended support release further down
FredMcD said
Separate Issue; Your System Details shows; Installed Plug-ins Shockwave Flash 20.0 r0 Shockwave Flash 15.0 r0
Having more than one version of a program may cause issues. You must remove the older programs. Then get the current full installer.
Thanks, but I'm pretty sure I did that on purpose, because there was a web page I wanted to use that was incompatible with the current version of Shockwave. I haven't had any problems with having the two versions both installed.