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

Hierdie gesprek is in die argief. Vra asseblief 'n nuwe vraag as jy hulp nodig het.

Application Handler Broken

more options

After opening a large number of tabs in rapid succession the application handler for Firefox no longer launches applications and either displays:

Firefox doesn’t know how to open this address, because one of the following protocols ([Whatever the protocol is]) isn’t associated with any program or is not allowed in this context.

Or simply does nothing

This occurs in safe mode and after a refresh. Other browsers (Chrome, Edge and Waterfox tested in this instance) but not Firefox previously I have got this working with a full uninstall and reinstall but it usually happens again after a few days

After opening a large number of tabs in rapid succession the application handler for Firefox no longer launches applications and either displays: Firefox doesn’t know how to open this address, because one of the following protocols ([Whatever the protocol is]) isn’t associated with any program or is not allowed in this context. Or simply does nothing This occurs in safe mode and after a refresh. Other browsers (Chrome, Edge and Waterfox tested in this instance) but not Firefox previously I have got this working with a full uninstall and reinstall but it usually happens again after a few days

All Replies (10)

more options

Hi Tyson C Rasanen , See if this article can help:

Firefox repeatedly opens empty tabs or windows after you click on a link

more options

Hey Robert,

In order of the solutions presented there:

  • I can say that all handles I CAN test don't work. So far I've texted NXM (Nexus's Vortex Mod Manager), Screenconnect-[GUID] (Screenconnect's native handle) and a generic mailto without success
  • I did try resetting handlers before posting. Sorry! Forgot to mention :)
  • I can say the PC has no malware per the scanners I have installed (Though given it works with other browsers I doubt you intended that one to be necessarily relevant anyways)
more options

While you're waiting for a response to your texts, have you checked your Windows file type associations?

Go to - Windows Settings -> Apps -> Default Apps (on the left) listed below the Reset button, you will see

  • Choose Default Apps By File Type
  • Choose Default Apps By Protocol
  • Set Defaults By App

Select *Choose Default Apps By File Type (it may take a minute for the list to load) find the file type and click on the line to the right of it to select an app.

Also check the others, if appropriate.

more options

Nothing out of the ordinary there. Like I stated earlier it DOES work on other browsers :)!

more options

There was a similar issue with a protocol not opening -

Check @jscher2000's response in this thread:

Firefox no longer able to open https://support.mozilla.org/en-US/questions/1274684

more options

Blasts, the about:config fix didn't work either

more options

Maybe you need to go on vacation like that user did :)

I'm about out of ideas but, I'll keep looking. Maybe someone else knows another trick or two.

more options

I'm not sure that it's appropriate here but, it looks interesting:

The Nexus Forums Manual Download (nxm protocol) https://forums.nexusmods.com/index.php?/topic/468427-manual-download-nxm-protocol/

The link in that thread for the ModManager is dead. I found it here: https://www.nexusmods.com/about/vortex/

more options

And maybe review the ScreenConnect Integration at:

Syncro Help Center https://help.syncromsp.com/hc/en-us/articles/360008240354-ScreenConnect-Integration#troubleshooting

more options

Looked through both of those, neither have helped in the past typically (Which would make sense given that other browsers still can access everything fine including a fork of Firefox)