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Tabs are not saving, "restore previous session" is greyed out, showQuitWarning = true.

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  • 35 have this problem
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  • Last reply by Dougo

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Problem started when I had a few windows open and I closed them and tried to open firefox in quick succession.

When I used to close firefox, it used to save my 800 tabs automatically, no message popped up when I closed, and when I opened firefox up again, all my tabs were there.

Now, when I close firefox, it warns me that I am closing 800 tabs. It gives me no option to save. When I open firefox back up, it doesn't let me "restore previous session," it is greyed out. However, I can go "recently closed windows" and use that to restore my session. Restarting firefox is also really slow now (I am not sure if it is closing or opening, but I suspect it is closing).

I have "show my windows and tabs from the last time" selected in options. I am not having it clear history on close. I set showQuitWarning, all options with "warnOn..." in them to true (only changed warnOnRestart), and privacy.clearOnShutdown.sessions to false.

I am not shutting down my computer until this is solved. These 800 tabs are important (will be about 500 after I finish culling, was 1365 yesterday).

Problem started when I had a few windows open and I closed them and tried to open firefox in quick succession. When I used to close firefox, it used to save my 800 tabs automatically, no message popped up when I closed, and when I opened firefox up again, all my tabs were there. Now, when I close firefox, it warns me that I am closing 800 tabs. It gives me no option to save. When I open firefox back up, it doesn't let me "restore previous session," it is greyed out. However, I can go "recently closed windows" and use that to restore my session. Restarting firefox is also really slow now (I am not sure if it is closing or opening, but I suspect it is closing). I have "show my windows and tabs from the last time" selected in options. I am not having it clear history on close. I set showQuitWarning, all options with "warnOn..." in them to true (only changed warnOnRestart), and privacy.clearOnShutdown.sessions to false. I am not shutting down my computer until this is solved. These 800 tabs are important (will be about 500 after I finish culling, was 1365 yesterday).

All Replies (2)

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Make sure that Firefox closes properly and that there isn't a hanging Firefox or plugin-container process left in the task manager.

Use "Firefox/File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit") to close Firefox if you are currently doing that by clicking the close X on the title bar.


You can check for problems with the sessionstore.js and sessionstore.bak files in the Firefox Profile Folder that store session data.

Delete the sessionstore.js file and possible sessionstore-##.js files with a number and sessionstore.bak in the Firefox Profile Folder.

Deleting sessionstore.js will cause App Tabs and Tab Groups and open and closed (undo) tabs to get lost, so you will have to create them again (make a note or bookmark them).

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I had a problem with the "restore previous session" greyed out in history box too. The problem for me was hyper-threading, common in Pentium 4 processors. Easiest fix is to type "about:home" in the address bar, enter, and click on restore last session in the home page. You can also go to the Firefox icon, right click, click properties, click compatibility, and select "run this program in compatability mode for" and select Windows 98/Windows ME. This essentially disables hyper-threading. Also may be a good fix if Firefox hangs a lot. (You can also disable hyper-threading in BIOS, but this is overkill). You can also reboot your computer: this clears the hyper-thread in RAM. Or you can use a RAM manager like Free Ram XP Pro, to clear the RAM cache of the thread before you start Firefox. Or, you can go to task manager, right click on firefox.exe in processes tab, and if you have a dual/multicore processor, set affinity (number of processors to use) to 1. See ''''Solutions and Known causes of Fx Freezing'''' for instructions on how to keep affinity set to 1. (If you don't see the affinity option in task manager, you don't have a dual or multi-core processor). Or you can upgrade your BIOS. It may help, but that's kind of radical if this is the only problem you're having.

Modified by Dougo