Hello can you try to use Firefox > Quit to close Firefox, don't close it from [X] on the title bar, and check it again.

see also : http://kb.mozillazine.org/Firefox_hangs#Hang_at_exit

thank you

I'm not exactly sure what you mean by "close it from [X] on the title bar." There are only Xs on the tabs, and they don't quit the app.

I was closing all tabs and windows by pressing command-w repeatedly, then quitting the app with command-q.

If I use the menubar instead, selecting File > Close Tab for each tab, then Firefox > Quit Firefox, the issue persists.

I've just discovered that if I don't close my tabs or windows, but instead simply quit the app (either by keyboard shortcut or menubar), the error message is not shown upon the app's next launch.

This would still seem to be a bug to me, since I don't believe closing tabs or windows before quitting an app should produce an error.

I have the same problem, and I have closed it with Quit Firefox, and it still happens.

create a fresh profile, make the settings changes desired, and compare to your current profile

http://kb.mozillazine.org/Category:Profiles

Assuming you use windows (I don't):

http://kb.mozillazine.org/Creating_a_new_Firefox_profile_on_Windows

If the problem is not present in a fresh profile migrate your settings to the new profile.

Deleting either the "profiles.ini" file or the "~/Library/Application Support/Firefox" folder temporarily solves the issue. However, once I change the FF app general preference "When FF starts" from the default "Show my home page" setting to any other value (or to another value and then back to the default value), the error resurfaces.

I am having the same problem. I am using a Macbook and since the most recent FF update whenever I open FF I get the error message. I have tried quitting all tabs before I shut down my computer with no luck. I have reset my homepage, also with no luck. This is very frustrating.

Using "Quit" instead of X doesn't solve the problem as the message "Well, this is embarrassing... " still appears. The only way to avoid it is to get back (using the back button on the tab) to the home page. This situation affects both, my iMac (10.8.3 Mountain Lion) and my HP ProBook (Windows 7).

Is there any fix for this? I have checked daily and see more and more people experiencing this problem, but no resolutions that are working.

Not as far as I know.

I get exactly the same as the first poster . I have also tried Reset Firefox To Its Default State and been to Firefox Preferences and selected Restore To Default. Nothing works. This happened after the update to 20.0

I guess the only fix is to uninstall Firefox and start using Safari, since we seem to get no response on the problem!

Safari is not an option for Mac users. The latest upgade is not compatible and also not compatible with other applications. Guess, Chrome will be the next best bet.

I have discovered if you hit the space bar on your keyboard when the message appears after you start Firefox , the message will disappear and you should see the Mozilla Firefox Start Page . Try it .

No, I get the page that Firefox says they can't restore.

hello, this should be addressed in a later version of firefox. as a workaround in the meanwhile you could try this: enter about:config into the firefox location bar (confirm the info message in case it shows up) & search for the preference named browser.sessionstore.resume_from_crash. double-click it and change its value to false.

Hi philpp, Thank you for reply, it fixed the problem. I did discover from playing around that it is all to do with how you go about exiting firefox . With a mac what I would normally do ( as I do with any open programmes ) is first to close the window by clicking on the red dot ( traffic light ) as I call them before clicking on Firefox and then selecting Quit Firefox. If you do not close the window first and just click on Firefox and then choose Quit Firefox the problem does not arise.

If this is corrected on a later version will I need to go back to ( about : config ) and change its value again ? .

the problem here is essentially that firefox 20 mistakenly classifies this way of closing the browser as a crash & will launch the sessions restore feature at the next startup of the browser. the key in about:config mentioned above will totally switch off the sessionrestore feature for crashes.

once the bug will be resolved (hopefully in firefox 21) i'd recommend resetting browser.sessionstore.resume_from_crash back to its default value true again, so that you get the benefit of a restored session in case firefox is really crashing sometime.

I imagine a lot of people close there programmes on their macs in this way. Anyway I made a note of returning the setting back to its default true value after the next Firefox update. Thanks again.

A possible cause can be that you are first closing all Firefox windows and then close the Firefox application.

Some have reported that closing Firefox (Firefox > Quit) while the browser window is still open works for them.

If I type in about:config, I get a message that says I'm comprising the stability, security, and performance of this application. Should I ignore that? It scares me since I don't know what I'm doing!