Hi pdegroot,

It sounds like your issue may be more network-related than browser-specific, especially since multiple apps (Firefox, Safari, and even Mac Mail) are acting up on your Mac, while other devices on the same WiFi work fine. This points to a possible local DNS, network stack, or macOS-level issue.

Since you've tried proxy changes, new profiles, and clearing caches, try resetting your Mac's network settings entirely or using a different DNS like 1.1.1.1 or 8.8.8.8. Also, consider testing in Safe Mode (to rule out third-party conflicts) or creating a new macOS user account to isolate the issue further.

Regards

Thank you for trying to help.

I've tried safe modes.

I don't know how to reset my Mac's network settings so I haven't done it.

I have set network proxy setting to: auto proxy discovery -but I have yet to see any evidence that there is a proxy involved.

It took a lot of work to figure out how to hack into my ISP's router. Officially it can't be done and the only access I have as a user is through a phone app which doesn't let me change anything.

One of the settings that Apple OS offers is "Private WiFi address" that can be "fixed". Fixed appears to be the default mode.

Another interesting setting is "Limit IP address tracking" which applies to both Mac Mail and Safari. The default mode appears to be "on".

It has been a very long time since I laboured to fix networking problems (as in not in this century). I can see potential conflicts between the security that Apple has put into its OS and what Norton wants to install.

The problem has not gone away.

I have managed to reset my Mac's network settings and I have tried safe mode many times.

Things now work for a while then slow down. Eventually they speed up again. The problems are still manifesting in Firefox, Safari, and Mail but less so in the latter. Firefox is disabled the most.

I have created a new Mac OS account but have not operated it long enough to see if the problems recur. I would have to enter a lot of bookmarks and passwords to duplicate my existing primary account.

Every so often I get a message that the name of my computer is already being used so a new name is provided. I am up to "computer name" 6.

I have a desktop Mac running Monterey. Problems with Firefox been going on for months and months, so long I've lost track. I kept upgrading Firefox thinking that would help (I'm now at 128.10.1) but that didn't fix anything. I had to switch to using private windows because every new window crashed. Now even a private window freezes, or doesn't open at all, and is slower than molasses in January when it does open.

I've been using Firefox for at least 15 years and never had a problem until recently. Now it is pretty much unusable. A single page take as long as 10-15 seconds to load, when and if it even does. Mail works okay, but links in an email sometimes will not open.

Why can't you fix this? I've tried all the proposed fixes, and nothing works. I've tried using Safari instead, which runs fine with no glitches, but I HATE Safari. It's a pain to use and doesn't have many of the features I always liked about Firefox.

I have found the cause of my problem. A single USB-C cable was plugged into two USB-C ports. I have no idea how I managed that but it has to have been my fault. Once I unplugged one end of the cable all my problems went away.

A USB cable is not the problem here. Sometimes Firefox is better in the morning, sometimes it is not. I am beyond frustrated.