Hello, if these extensions were Legacy extensions (not updated to WebExtensions format) they were automatically disabled and/or removed.

To find replacements for these extensions, try this helpful website: https://mozilla.github.io/extension-finder/

If this solved your problem/answered your question, please mark as solution.

Agreed.

Thanks for trying. The 5 Extensions that work for me for Firefox 57 cannot be legacy ones.

Hi  !

Would you please take a look at this thread :

https://support.mozilla.org/en-US/questions/1136981

Is this similar to your situation  ?

Thanks for trying. It is not about recovering passed extensions after refresh. Is about new extensions added after refresh, that works well, but after reboot, disappear.

A bit more detail and discovery. Even though my Extension listing looks or appears empty, the 5 add on items are working because I enabled them, used them, before I shut down and rebooted later to use the computer again, and I can use these 5 add on properly. So, only that the extensions are listed for me to see and make changes.

This is strange. That means I cannot disable one or two of the 5 add on items if i need to. How to fix this?

I meant that the 5 add on items are still functioning, but they do not appear in the Extension listing (empty).

For instance, my Easy Download works, but there is nothing listed in the Extension listing. The prompt says: "You don't have any add-ons of this type installed; Learn more about add-ons"

This means I cannot select add-on items to disable or remove. How can we solve this problem.

Open the Add-ons Manager. Is there a legacy button?

It is possible there is a problem with files in the profile folder that store the extensions registry.

Delete the extensions.* files (extensions.json, extensions.ini, extensions.sqlite) and compatibility.ini in the Firefox profile folder with Firefox closed to reset the extensions registry.

• https://support.mozilla.org/en-US/kb/Profiles

New files will be created when required.

See "Corrupt extension files":

• https://support.mozilla.org/en-US/kb/unable-install-add-ons-extensions-or-themes
• http://kb.mozillazine.org/Unable_to_install_themes_or_extensions

You can check if there is a update available in case of issues.

• click the cogwheel button (left of the Search bar) on the about:addons page to "Check for Updates"

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 the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Sorry FredMcD, as mentioned, these add on items are new working extensions that worked my Firefox 57; not legacy items. Thanks anyway for trying.

Thanks Cor- el, I have done what you suggested on my PC before; before asking for help. I will do them again, just in case one of them will fix the problem this second attempt. I will let you know.

Dear Cor-El, after closing Firefox, I renamed the following profile items as ".OLD" and it corrected my problem for now: 1. Compatibility settings (not sure if this is .ini file) 2. extensions.json

I will reboot, and see if the extension list is still showing, and will let you know. Cheers

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

fyi for future :

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer
• https://support.mozilla.org/en-US/kb/import-bookmarks-html-file
• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Dear Cor-El, I rebooted and the extension list is still showing for Firefox. Problem solved. So it is the removing of the Compatibility Setting and Extension.json files that solve my type of problem; where add on items work and continue to work while the extension list is not displayed. Many thanks.

Dear Cor-El, The problem came back two days later, when I boot up to use the computer again, and extension items continue not to appear (none listed), however, in the top bar of browser, I can see that the 3 add-ons are active and working.

I have uninstalled all Firefox related software from the computer, restarted the computer and then reinstalled new Firefox. The extension list remains empty, day after day.

This seemed to be a problem for some other users, and hope mozilla can do something about it.

So far all suggestions were tried and failed, including adding missing profile files, etc. So I will not try any more suggestions and leave it to Mozilla if they can look into it. Many thanks

Did you try once again to delete extensions.json and possibly compatibility.ini ?