You can try setting network.seer.enabled to true. You can try to reset the prefs that do that to see if it'll reverse the action

• Navigate to about:config in your Address Bar
• Press the "I'll be careful, I promise!" button to proceed
• Search for network.seer.enabled and double click it to set it to false

Mozilla is releasing 29.0.1 as an update to Firefox 29 sometime Friday to alleviate some of the most commonly reported problems here on the forum. You will want to get that upgrade by going to The image "new fx menu" does not exist. > Help > About Firefox and let it upgrade there.

Thanks Moses, but network.seer.enabled was already on "true" (see snapshot)

Riccardo

I meant to say set it as false

I had edited my reply earlier but I figured wouldn't see it. Try setting network.seer.enabled to FALSE

I tried to set to false, but still have such problem. Using different way to exit Firefox and trying to start it again after window was closed, generate "Firefox is already running but not responding. To open a new window you must first close ...." . It's strange it never happen with previous version of Firefox.

Thanks riccardo

Mozilla is releasing 29.0.1 as an update to Firefox 29 tomorrow to alleviate some of the most commonly reported problems here on the forum. You will want to get that upgrade by going to The image "new fx menu" does not exist. > Help > About Firefox and let it upgrade there.

Will try and let you know.

riccardo

Hi Moses, with 29.0.1 it seems it work correctly.

Riccardo

Awesome! :)

I still have the problem with 29.0.1 (and the previous version). To solve it I unticked, 'Clear History When Firefox Closes', in Options. No idea why this works..

For those that have the problem after the update or after changing the seer preference please set Firefox to NOT delete history at closedown

1. Use new Button -> Preferences ->
   |Privacy|Firefox will : [Remember History v]
2. Does that help and allow you to restart ok ?

• Note
  1. You should be able to open and use Private Browsing Windows ok still. You may need to close those windows before closing down Firefox though.
     See Private Browsing - Use Firefox without saving history
  2. This hang or close down issue is a known bug in Firefox 29 that has yet to be fixed. With luck it may be fixed in the next Firefox version.
     Note the known issues mentioned in
     http://www.mozilla.org/en-US/firefox/29.0.1/releasenotes/

I have the same hang up issue with FF v 29.0.1 win 7 x 64. I as certain the You Tube download add-on; "Download YouTube Videos as MP4 1.7.18" is causing this problem on my machine. If I remove the add-on, FF works fine. With the add-on FF hangs up on exit. Anyone has any suggestions?

This particular issue I am aware of may happen with different actions and addons and may sometimes only be noticed intermittently after repeated close downs, the common factor and the workaround to stop that is to set Firefox to remember History as explained in my post above.

If you set Firefox to remember History and the problem goes away it is probably the known bug, and you will need to wait for Firefox to be fixed properly.

If you have Firefox set to remember History and still have a problem then as it will be a different issue please start a thread of your own by asking a question.

1. Please use this Special Link for questions on this problem of Firefox 29 won't start, hangs when History is NOT cleared on closedown.
   • _{or this Special Link if you have problems and History is cleared on close down.}
2. Please ensure you follow the prompts to include full troubleshooting information when you post your question. There is a green button to help automate that task.
3. Please mention in this thread of Riccardo16's when you have started your own question. Others may wish to follow the progress and help you.

I setted Network.seerto false but the problem lasts. Firefox stays active in processes after closing the window. I have the most recent version of Firefox.

M.L.

(Personal information removed by Moderator. Please read the Mozilla Support rules and guidelines -m)

UPDATE

Note one potential fix is now in the very recent Firefox Beta 30b8 Initial reports suggest this fixes the issue. ^{(Bug1005487#c38)} If you have been suffering from this problem and want a fix now instead of in a few weeks time you may wish to download and install the Beta version of Firefox.

The beta version is effectively a release candidate but is only intended for advanced users or testers. I would be interested to hear feedback from those of you that do test this out.

Beta version download

• http://www.mozilla.org/en-US/firefox/channel/#beta/beta-desktop

Thanks john99. I downloaded the beta v30.0 following your advice. It looks fine so far. Also another positive; it did not make my main menu bar "File Edit View etc" disappear as it did in v29.0. Looking forward to the final v30.0 release.

I have uninstalled the (recent) version of Firefox and reinstalled it. The problem is solved (up to now). 140530

Kind greetings

M.L.

Everyone Comments appreciated if you decide to try the Beta channel for a fix.

Magile, If reinstalling the current version solved your problem maybe it had a slightly different causes. Plain reinstalls do not often fix things unless you are on an old outdated version of Firefox. (Firefox 29.0.1 did include a fix for one similar issue a cause of some hangs )

I am interested really in the problem that the Beta channel Firefox is intended to fix.

HPWC, Thanks good to know it worked for you and was also an improvement in other respects.