Firefox not happy with El Capitan.

No problems here.

When using Firefox 41.0.1 my MBP has shutdown and restarted 2x so far. Frustrating! Not sure if there is a fix for this?

Try looking/posting here.

Firefox

Yes, Firefox is very unstable in 10.11. For me it is worst when opening a new window. If I keep one tab and only create new tabs it is more stable.

Mainly I get a crash saying somehting about: libobjc.A.dylib@0x7e5d

As can be seen here: https://crash-stats.mozilla.com/report/list?product=Firefox&range_unit=days&rang e_value=14&signature=libobjc.A.dylib%400x7e5d#tab-comments other people experience this as well (though there is still no bugreport for it on the Bugzilla tab). 100% of these reported crashes are on 10.11.

There's a FIrefox 41.0.2 on the way but it isn't quite ready yet.😟

Same here. Firefox crashes about ten times a day. Often while opening a new window. Sometimes just in the background. Firefox update to 41.0.2 didn't help.

The only Firefox 41.0.1 plug-in that I use is the current release of Firebug. For me, Firefox works flawlessly on El Capitan. Systematically remove any additions that you may have added to Firefox 41.0.1 to determine which one is causing the mischief.

I am also having problems with firefox with el capitan also. Have to restart it all the time. Seems like it can't access the network after a while.

I've stopped using FireFox because the issues with El Capitan are so bad.

With 10.11 it would randomly crash but it would not affect anything else and you could just go to the dock and start it again.

In the "bug fix" update 10.11.1 a FireFox crash goes much deeper. If I try to relaunch FireFox the icon will just bounce in the dock. Activity Monitor will not show the process but Force Quit will. Force Quit will not, however, force quit it no matter what. At this point I cannot restart or shutdown, and have to do a hard reset via the power button.

Side note: overall 10.11 was bad, 10.11.1 is even worse, and I'm contemplating a downgrade to Yosemite or Mavericks.

Same for me. Often when i left FireFox open with no tab for ahile and i get back to the program it crashes. I think i've sent 50 crash reposrts so far.

Same behavior for new tabs as described from others. Annoying... It's still present in 41.0.2... if it keeps crashing i have to use another browser for El Capitan. No problems with Yosemite.

...was also a libobjc.A.dylib@0x7e5d crash.

I lost a couple of days of productive time to the 'upgrade'.....Went through every possibility to address 'pinwheel freezes' & crashes before finally going to firefox and updating ('refresh') my browser application... since then, according to my Activity Monitor, my memory usage for firefox went from 7GB to 250MB! No more pinwheel or page delays. Thanks for the tip!

FWIW, Firefox 42.0 is about to be released. Rather than updating to it, you might want to download the installer and save the version of FF 41 that's working for you before installing 42, at least until 42 confirms functionality.

Same thing happened to my pro. Firefox crashes when I watch video on full screen mode. ...Now I have to switch to Safari...

Firefox 42 crashes on start up on my 2015 MacBook Pro 13" Retina. Trashed the preferences and now it seems to work.