Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

cannot install [any] addon - for this instance though, it is UBlock Origin I require

  • 4 replies
  • 1 has this problem
  • 29 views
  • Last reply by FredMcD

more options

Search for the addon on mozilla addons.

Locate UBlock Origin and click install. The popup is displayed to 'accept' permissions. Click accept and nothing happens. In the addons 'extensions' tab, the ublock entry row shows, but it never starts to download (and therefore never installs).

Tried to do it by saving the xpi to local and installing from there, but exactly same thing occurs.

Firefox 60.x ESR on Linux (slackware).

Is there anything else I might try please ?

Search for the addon on mozilla addons. Locate UBlock Origin and click install. The popup is displayed to 'accept' permissions. Click accept and nothing happens. In the addons 'extensions' tab, the ublock entry row shows, but it never starts to download (and therefore never installs). Tried to do it by saving the xpi to local and installing from there, but exactly same thing occurs. Firefox 60.x ESR on Linux (slackware). Is there anything else I might try please ?

All Replies (4)

more options

Are those legacy addons? And disable Ublock before any addons install to verify it isn't blocking or preventing installs.

more options

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

Type about:support in the address bar and press enter.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

Linux: Under the page logo on the left side, you will see Application Basics. Under this find Profile Directory. To its right press the button Open Directory.

Delete all extensions* files and compatibility.ini in the Firefox profile folder to reset the extensions registry.

New files will be created when required.

After, restart Firefox.

See "Corrupt extension files":

more options

Thank you both for replying.

@WestEnd, no not legacy and I am only installing Ublock Origin..no others installed; however, read the next bit.

@FredMcD, thank you for that full answer. Unfortunately this did not change the situation. The [ublock origin in this case] addon will not install, but...

I noticed a 'debug addons' option in 'about:addons'. There is a 'load temporary' button and a 'debug' checkbox etc.

On debugging the latest 'ublock origin' addon, it gave the following:

"DEPRECATION WARNING: Search service falling back to synchronous initialization. This is generally the consequence of an add-on using a deprecated search service API. You may find more details about this deprecation at: https://developer.mozilla.org/en-US/docs/XPCOM_Interface_Reference/nsIBrowserSearchService#async_warning jar:file:///usr/lib/firefox/omni.ja!/components/nsSearchService.js 2675 SRCH_SVC__ensureInitialized jar:file:///usr/lib/firefox/omni.ja!/components/nsSearchService.js 3839 SRCH_SVC_getEngineByName chrome://browser/content/browser.js 3883 addEngine chrome://browser/content/browser.js 3751 addSearch chrome://browser/content/browser.js 3712 receiveMessage..."

Which means little to me at the moment. I will go away and digest it.

Interestingly, temporary loading the addon works...but when quitting out of debugging, it seems to ditch the addon....I was hoping it would keep it :-) to act as a workaround for now. Ho hum.

more options

I called for more help.