Hi Andrew, In Windows Settings -> Apps -> Default Apps -> Set Defaults by App you should see htm, html, http and https set for Firefox (see screenshot).

Thanks but these are already set as FF as default.

Hello again, Are the hyperlinks for opening files, like pdf's, or for websites?

Websites

Hi, Firefox has a Safe Mode which disables your add-ons. You can rule out those as interfering with hyperlinks. Click the Menu button (3-bar button) Select Help Select Restart With Add-ons Disabled Firefox will start up with the Firefox Safe Mode dialog. Don't choose Refresh. Try a hyperlink and see if it opens in Firefox.

To Exit Safe Mode close Firefox.

Thanks but that unfortunately doesn't resolve the issue.

Andrew, I've looked through some other posts with the same issue and it appears that you might have some Registry problems. Hyperlinks from any program other than firefox will not open hyperlink in outlook will not open

You may need to completely uninstall Firefox, clean up your registry and re-install Firefox. You will be able to restore your Profile with all of your bookmarks, passwords, history, etc. See these articles: Back up and restore information in Firefox profiles Firefox keeps crashing at startup (Scroll down to Try a clean install)

Of course, you can wait to do this, and maybe someone with a less dramatic solution can help.

Thanks for your help My_Cheese_Is_Slippin'.

I've just upgraded to Firefox 68 and it now functions as expected.

Great news! I'm glad that you didn't have to go through a time consuming solution.

I am now using 70.0 (64 bits) and it still won't open external application links, namely MS Teams, Zoom (Video conferencing) and other applications I don't recall at the moment. When I paste the link in another browser to click on the link, it works fine.

I tried without any extensions with the same result. This is really annoying when I get to my agenda to start a meeting i'm invited in.

It used to do it until recently, so something has changed in the latests versions.

Well, the issue is gone just before I was about update to 70.0.1. I guess the first fix in the relase notes did the trick! thanks.

Who should we blame for this bug, Microsoft or Mozilla? I had the same problem with one of my FF versions (don't remember which) and the workaround was to change the default browser back to Edge and then FF again. I'm now using FF 70.0.1 and this solution doesn't help all the times.

Interesting. I'll remember to try that if I experience this issue again.