Extensions that do not have a "Remove" button are installed globally by other software and are not under control of the Firefox extension manager. Globally installed extensions are usually found via a registry scan or are installed in a location that Firefox scans for installed extensions.

• https://developer.mozilla.org/Installing_extensions
• https://developer.mozilla.org/Adding_Extensions_using_the_Windows_Registry

Extensions installed this way need to be removed via the settings (options/preferences) of the program that has added this extension or this program has to be uninstalled via "Control Panel > Programs". In Firefox you an only disable such an extension.

You can check the extensions.json file in the Firefox profile folder for details about extensions.

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

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

You can open the file in the Scratchpad ("3-bar" menu button or Tools > Web Developer). Click the "Pretty Print" button to format the file for readability.

Cor-el,

While this didn't fix my problem, it did make me realize that the add-on, which is from Logitech is version 6.5 and the program it came from has been updated to version 6.67 (and doesn't include the add-on anymore).

I now realize that I"m going to have to either: A) Contact Logitech about how to remove it. B) Completely uninstall Firefox and all settings/links/add-ons/etc, then completely wipe all traces of FireFox out of the Registry, then do cleanup, then reinstall from scratch.

Did you open the extensions.json file in the Firefox Scratchpad to check the installation path of the extension like I wrote above?

That should give you the location of the extension and would allow to remove the extension.

You can also check the Windows Registry.

HKLM\Software\Wow6432Node\Vendor\Name\Extensions\<extension-id>

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

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

See also:

• https://developer.mozilla.org/Tools/Scratchpad

It was actually by opening the extensions.json that I was able to determine which program it came from, and that it's from an older version of the "donor" program (currently now on version 6.67).

part of extensions.json

{"id":"{F003DA68-8256-4b37-A6C4-350FA04494DF}","syncGUID":"7l0nJttwaNGI","location":"winreg-app-global","version":"6.5","type":"extension","internalName":null,"updateURL":null,"updateKey":null,"optionsURL":null,"optionsType":null,"aboutURL":null,"iconURL":null,"icon64URL":null,"defaultLocale":{"name":"Logitech SetPoint","description":"Smooth scrolling for Logitech mice.","creator":"Logitech Inc.","homepageURL":"http://www.logitech.com/"},"visible":true,"active":false,"userDisabled":true,"appDisabled":true,"descriptor":"C:\\Program Files\\Logitech\\SetPointP\\LogiSmoothFirefoxExt","installDate":1443275752747,"updateDate":1443275752747,"applyBackgroundUpdates":1,"bootstrap":false,"skinnable":false,"size":24801,"sourceURI":null,"releaseNotesURI":null,"softDisabled":false,"foreignInstall":true,"hasBinaryComponents":false,"strictCompatibility":false,"locales":[],"targetApplications":[{"id":"{ec8030f7-c20a-464f-9b0e-13a3a9e97384}","minVersion":"6.0a1","maxVersion":"99.0.0.*"}],"targetPlatforms":[],"multiprocessCompatible":false,"signedState":0,"seen":true}

====

The directory exists with 4 items:

• Folder: chrome
• File: chrome.manifest
• File: icon.png
• File: install.rdf

contents of the "install.rdf"

<RDF xmlns="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:em="http://www.mozilla.org/2004/em-rdf#">

 <Description about="urn:mozilla:install-manifest">
   {F003DA68-8256-4b37-A6C4-350FA04494DF}
   2
   Logitech SetPoint
   6.5
   Logitech Inc.
   

http://www.logitech.com/

   Smooth scrolling for Logitech mice.
   
     <Description>
       <em:id>{ec8030f7-c20a-464f-9b0e-13a3a9e97384} 
       6.0a1
       99.0.0.*
     </Description>
   </em:targetApplication>
 </Description>

</RDF>

====

It appears that this "install.rdf" is left over from the old SetPointP program. I'm not finding any way to uninstall.

So, question: If I delete the info from the *json and reboot, would that work?

I tried that, as well as going through the registry and deleting references to the "F003DA68..." and "LogiSmoothFirefoxExt" (there was only 1, same item for both). I've got to reboot to know if it worked.

Solution:

Deleting the "entry" in the extensions.json and deleting the one registry key (found by searching for "F003DA68") has removed the add-on from the Extensions section.

Effects: It now appears that my mouse is scrolling better in firefox. The new version of SetPoint (v6.67) has a different program that doesn't add an extension and the old one may have been blocking it. Time will tell.