No, there is no limit to the number of tabs although a very large number will probably slowdown Firefox.

Do you give Firefox enough time to close completely and do you quit the Firefox application with the windows still open?

Use one of these to close Firefox if you are currently doing that by clicking the close X on the Firefox title bar.

• "3-bar" menu button > Exit (Power button)
• Windows: File > Exit
• Mac: Firefox > Quit Firefox
• Linux: File > Quit

Thanks for the reply. I considered that as well, but that isn't it.

It even happens if I choose "Save Session" with Session Manager for example, and that doesn't involve closing Firefox at all.

And keep in mind that this only happens with Firefox 45.0, not with 44. I'm not doing anything differently as far as closing out of Firefox between the two versions.

Hi there,

I did also notice this problem but it already started with FF 42....

I already tried resetting the browser settings, disabling all add ons, deleting places.sqlite/history and running a fresh profile but the error remains.

I also checked sessionstore.js and session.rdf and noticed that certain tabs are stored with an empty url (about:newtab) or any random url that was used last (e.g. the home url).

I can reproduce the error when opening a new tab (next to others), running any Google search, leave all tabs open and exit Firefox. The next time I open the last session this newly created tab is empty or addresses any older url from the browser history.

This error also affects the tab history itself. The forward/reward buttons don't work properly or are navigating to the wrong address, opening any previously closed tab restores the wrong url.

Seems to me like a bug since the cookie handling changed with FF42 although it has nothing to do with it.

I only found one similar topic in the support forums but there was no real solution...

https://support.mozilla.org/en-US/questions/1103160

Best regards, pocci

Create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

I already tried resetting the browser settings, disabling all add ons, deleting places.sqlite/history and running a fresh profile but the error remains.

Please also note that I this bug is showing up on two different PCs with different add ons and different profiles...

This is one of the most horrible problems for me that I've ever dealt with on any browser.

I'm not sure if it's as severe for everyone, but I use a lot of tabs and wind up having many open at any given time... and because of that, I am having to pick through months of history all the time to restore what was destroyed by the browser.

The fact that it constantly crashes by freezing up for all eternity doesn't help the issue, but when I am forced to use task manager to close firefox and reload it, every single tab other than the one that was loaded at the time of the crash is turned into a "new tab", and I can't hit "back" or anything. I am losing track of a lot of things and it's utterly tormenting me, because it crashes every day, and every time it does, boom, it's all nuked.

I can't just go through and delete all my history to "fix" the problem, because that's my only link to all the things that have been removed before I could finish with them.

I'm posting here although others have because this NEEDS to be a HIGH PRIORITY ISSUE and not one to take time getting around to fixing. This is a REALLY bad problem for people who actually use a lot of tabs and RELY on firefox to remember sessions instead of DELETING them.

Thanks, there's some comfort in knowing I'm not the only one facing this issue.

I hope that a solution can be found because I can't upgrade until this is fixed.

Separate Issue; Your System Details shows;

Installed Plug-ins

Garmin Communicator Plug-in Version 2.9.3.0 Garmin Communicator Plug-in Version 4.1.0.0
Having more than one version of a program may cause issues. You must remove the older programs. Then get the current full installer.

Thanks Mozilla, I'm going to need to be committed before it's over and done because this is driving me completely insane.

I am literally spending every day now picking through my history. I've been picking through my history for over a week now, and I still have to pick through it some more. I crashed again today. Great. That lovely thing where the screen turns white, and the top bar says "not responding" then vanishes, then comes back, then vanishes, etc. for all eternity. Great feature that. But the real problem isn't the crashing. It's the DELETION OF ALL MY TABS.

I have for so long held Firefox in the highest esteem among browsers. I cannot believe a problem so severe as this goes ignored, and it seems like there's no DIRECT way to contact support with a truly pressing issue like this. This is AFFECTING MY DAILY LIFE. This is NOT a minor issue.

At this point, I feel I have literally no choice but to go on a hunt to try to find another browser that even remotely offers what I found in this one, but I am so unbelievably furious right now. This is freaking inexcusable. I'll probably get in trouble or something for ranting here, but there's no way for me to contact support DIRECTLY since they so cleverly don't seem to have a way available to do that. Who does that? As if this problem isn't enough, I can't even get in touch with someone about it... this... system... is not sorting the problem out AT ALL.

We show up, post about it, mark we have the problem also, etc... but it does anyone from Mozilla actually come and address these issues?

I don't know what to say. It doesn't matter at this point because I am forced to choose. My once favorite browser will forever delete my tabs and sentence me to picking through my history instead of, I dunno, living my life, or I have to go find another browser. Oh, that also means I have to pick through all my bookmarks and...

This is utterly ridiculous.

I was one of the most loyal to this browser, and I feel like this past couple of months of this perpetual torture has inescapably reversed that opinion. I mean, I couldn't keep using Firefox if I wanted to. I can't spend the rest of my life cleaning up after my browser just because it can't avoid randomly crashing AND deleting my stuff.

Worst. Feature. Ever.

OK. So it looks like I found the source of my issue: UnloadTab. I just upgraded to FF 48.0.2 and disabled UnloadTab and that seems to have fixed the issue for me. I also checked the UnloadTab homepage at https://addons.mozilla.org/en-US/firefox/addon/unloadtab/?src=api and many commenters are describing the exact same problem that I have.

I did like this add-on a lot. Hopefully I can find a stable add-on that achieves something similar.

That was very good work. Well done. Please flag your last post as Solved Problem so others will know.

Keep an eye on their support site, they may fix it.