Current Firefox releases require extensions to be signed to prevent abuse. Extensions need to be signed with a certificate to make it more difficult for malware to install extensions.

• https://blog.mozilla.org/addons/2015/02/10/extension-signing-safer-experience/

It is possible that there is a problem with the file(s) that store the extensions registry.

Delete the extensions.* files (e.g. extensions.json, extensions.sqlite, extensions.ini) 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 or not compatible extensions in "Firefox 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 hasn't helped then also delete the addons.json file.

I deleted all of those files and then restarted the browser. It asked me for each extension if I wanted to install them, and I said yes. Then I went to check again and they all have that message on them.

The extensions which are hosted on the Mozilla Add-ons site should be signed, including Adblock Plus, Pushbullet, and YesScript. Can you make sure you have the current versions? For example, try updating from the Add-ons page, either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then look for the "gear" icon above the list and "Check for Updates".

No updates found.

Hmm, what versions do you have? You can copy/paste the list including the version numbers from the support information page. Either:

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

Scroll down to the Extensions heading, use the mouse to select from there through the table that follows and copy, and then paste into a reply. It will look a little messy, but don't worry, we're used to it.

Name Version Enabled ID Adblock Plus 2.6.7 true {d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d} DigitalPersona Extension 5.0.0.4490 true otis@digitalpersona.com RoboForm Toolbar 7.9.15.0 true {22119944-ED35-4ab1-910B-E619EA06A115} YesScript 2.0 true yesscript@userstyles.org Pushbullet 40 false jid1-BYcQOfYfmBMd9A@jetpack

Pushbullet was disabled, it's now enabled.

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) to see if that helps to check for updates of all extensions.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

Adblock Plus You have: 2.6.7 Current version: 2.6.11 Suggestion: Update by reinstalling from: https://addons.mozilla.org/firefox/addon/adblock-plus/ (no need to remove the old version)

YesScript You have: 2.0 Current version: 2.1.1-signed Suggestion: Update by reinstalling from: https://addons.mozilla.org/firefox/addon/yesscript/ (no need to remove the old version)

Pushbullet You have: 40 Current version: 283 Not sure if this is the same extension! Compare: https://addons.mozilla.org/firefox/addon/pushbullet/

One reason an extension might not be able to update is if it was installed "locally", for example, by drag-and-drop onto a Firefox tab instead of directly from the Add-ons site. In that case, Firefox doesn't store the source site information and doesn't check there for updates.

OK jscher2000, all of those are now updated. I still have the two that aren't. And now I see that my flash player and Reader are not up to date again, but I think someone said that's a known bug and I'm good there.

Hi UnusuallyClueless, I think the other extensions were from other sites, so you would need to search those out for updates.

For the Flash plugin, Adobe usually installs a Flash updater that runs at Windows startup, so that should take care of itself the next time you restart Windows. Or if you rarely do that (like me) you can get a Flash installer from this page:

https://www.adobe.com/products/flashplayer/distribution3.html

In the first table, it's the row for "plugin-based browsers" and either the EXE or MSI will work.

For Adobe Reader, the plugin check site has had problems with the version numbering of the Reader DC plugins. You might just use Reader's bulit-in Help > Check for Updates function from time to time to watch for the quarterly updates.

The DigitalPersona plugin can't be updated and can't be removed. I guess I have no choice but to disable it and just ignore that it's there. Thanks jscher2000 for your help!

Extensions that do not have a "Remove" button are installed by other software and are not under control of the Firefox extension manager. Such 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.

It was part of HP SimplePass Identity Protection (fingerprint login) which I never use. I uninstalled it.