Links in Mac Mail open 2 Firefox windows instead of tabs in Monterey 12.3

JustForComment wrote:

Since upgrading from our old 2011 iMac to our new M1 2021 iMac on Monterey 12.3 a week ago, clicking on a link in a Mac Mail email message opens 2 Firefox windows instead of 2 Firefox tabs if Firefox is not already open, even though "Open links in tabs instead of new windows" is selected in Preferences | General in Firefox, with Firefox as the default browser.

—Quit both Firefox and Mail and relaunch both, and test again...

If no insight or resolve

—Try in comparison changing your default browser to Safari and test in Safari this behavior. It may be telling.

Make Safari your default web browser on Mac - Apple Support

Welcome to the Apple Support Communities.

Try to use Safari instead of Firefox: Safari - Apple.

You should also change the default web browser on your Mac to Safari: Change the default web browser or email app on your Mac - Apple Support.

Jack

JustForComment wrote:

If Safari is the default browser, only one window is opened. But I don't want to use Safari and it's worked fine in Firefox for years.

Understood.



" —Try in comparison changing your default browser to Safari and test in Safari this behavior. It may be telling."

It is not a perfect science— Safari works as expected— this was a test.

Just because Firefox worked for years is no guarantee of anything, macOS 12.3 has not been around for years. Full stop.

For your third party app

— contact Mozilla or search their support/Help/FAQ/Known issue/updates

Firefox Help - Mozilla Support

Contact a third party vendor

Contact a third-party vendor - Apple Support

JustForComment wrote:

I've since discovered this problem has been around as long as I've been using Firefox, but it's the first time I've encountered it.

I have been using Firefox as my main working browser since 2004(?) I do leave Safari open, as the default browser however.

You can always try a safe boot and test your Firefox—

SafeBoot — https://support.apple.com/en-us/HT201262

Takes noticeable longer to get to the login screen, does a 5 minute disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache,  etc. 

Login and test. Reboot  as normal and test.  Caches get rebuilt automatically.

In Safe mode third party system modifications and system accelerations are disabled, it removes malware, etc hampering smooth operation, however a  reboot will put it back to normal mode.

This test will tell you if third party interference; extensions etc are not loaded in safe boot mode. 

This is a known and inconsistent issue with Firefox. It's not related to Monterey. I have seen the same problem from time to time all the way back to High Sierra. To date there has been no fix for it.