App (pinned) tabs and Tab Groups (Panorama) are stored as part of the session data in the file sessionstore.js in the Firefox profile folder.

• http://kb.mozillazine.org/Profile_folder_-_Firefox Firefox
• http://kb.mozillazine.org/sessionstore.js
• http://kb.mozillazine.org/Session_Restore

Make sure that you do not use Delete browsing, search and download history on Firefox to clear the "Browsing History" when Firefox is closed because that prevails and prevents Firefox from opening tabs from the previous session.

If you use cleanup software like CCleaner then make sure that Session is unchecked in the settings for the Firefox application.

This answer didn't work in my situation. I checked my setting and all were set to allow tabs and browsing history to be saved. I reset my app tabs and they disappeared again after shut down. I use Advanced System Care 4 Pro as my maintenance program and run it once a week. I changed the setting in System Care 4 to not clear history. I have something going on though. This started after my install of Firefox 5. I didn't use app tabs before installing Firefox 5 but I did have open tabs which were always there. I will keep trying to correct this, as now it has become a challenge. Thanks for the post though I did learn a few things and did consider it helpful.

I have also just checked some settings In the Orange Firefox tab at the top in the History section the Restore Previous session, Recently Closed Tabs, and Recently Closed Windows, are all grayed out. I also opened several tabs at different websites and after I rebooted they were gone. I have my setting set to Show My Windows and Tabs From Last Time. Maybe a reinstall of Firefox 5. I will try to reinstall 5.

Make sure that you do not run Firefox in permanent Private Browsing mode.

• https://support.mozilla.com/kb/Private+Browsing
• You enter Private Browsing mode if you select: Tools > Options > Privacy > History: Firefox will: "Never Remember History"
• To see all History and Cookie settings, choose: Tools > Options > Privacy, choose the setting Firefox will: Use custom settings for history
• Deselect: [ ] "Permanent Private Browsing mode"

I have checked all setting and even reinstalled Firefox 5 but still have the same problem. I never use private browsing or any other of the browsing history setting as I do have certain sites that I always leave tabs open. I can't leave any tabs open and shut down without having to reenter them after start up. I didn't have this problem with version 4 or any version before that.

Right now, for this problem as I have it, the solution is to make sure you close the window with the app tabs last. It seems that Firefox will count the lack of app tabs on the last window closed the same as removing the app tabs manually.

Given App tabs don't cross windows currently this doesn't surprise me. If you use multiple windows often, for now at least, this feature will only be useful if you want to minimize tabs.

I will give this a try. I also use Too Many Tabs so guess I will just go back to using them and adding a page or two to my Home page button.

I have the same problem plus each time I reboot I lose ALL of my history. Following above suggestions, I have checked all of my settings. Using Tools>Options>Privacy I have it set to Remember History. But it "forgets" all history as soon as I close Firefox. Please keep working the problem. Thanks.

This is a Firefox 5 issue. In Firefox 4 they worked beautifully. I loved them. They saved me a lot of time. I hate it when you "fix" something that worked!

If session restore isn't working properly then App Tabs and Tab Groups do not work.
That only works if the current session data is saved in the file sessionstore.js in the Firefox Profile Folder.

If you use cleanup software like CCleaner then make sure that Session is unchecked in the settings for the Firefox application.

I have went through all my security software and checked the setting and properties values and found nothing set any different than they always have been. I believe Firefox 5 has a bug and will most likely be fix in an update. I also have noticed that after shut down,(I have 4 homepage tab set), and I have to click the little house on the task bar to get them to open back up. All these things are new problems in version 5. I do hope Firefox isn't getting like MS and releasing their new versions before they are really ready. That's why I went to Firefox in the first place.

I have seen the same behaviour since upgrading to Firefox 5 on Apple Mac. I created 3 x App Tabs. Sometime they are persistent after I exit Firefox, and other times they are not. I have seen the symptom appear when as per another posters comments, you close the App Tabbed window before closing a new window that has no tabs. This seems to reset the history so there are no App Tabs.

This isn't the only scenario however, and today I just quit out of Firefox as it was acting slow, which is unusual on my 8-core Mac Pro. When I started up Firefox 5 again my App Tabs were gone, and the usual promt to open previous tabs never appeared either.

I have seen this happen approx 5 or 6 times now. I don't use any Cleaner apps, nor have I cleared history or cache recently.

Seems to be a new and real issue with FF5.

Regards, Dave

I am also having the same problem. I compared my settings under Tools > Options with my other laptop running FF 4.0.1 and they are the same. While I do use CCleaner, I have purposely not run it or cleared the cache in the past 24 hours feeling that was the problem. My tabs have disappeared anyway.

Thought this might be something to do with my new computer running Win7Pro but a check with a neighbour running FF5 on a Mac and my daughter using XP show they have the same problem.

This does appear to be an issue with FF5. Please issue update with this fixed.

Thanks, Theresa

it is so stupid when they think they can save app tabs on sessions, i am a web designer i must always clear cache ... to make sure all my change is right, but when i clear caches ... all may app tabs has gone, oh god... i need to create app tabs and group and i clear caches and i create tabs and group ... it is going to make me angry, i just think app tabs save my time but now i see it take me more time to manage app tabs, so i tried chrome now.

I got new problem, i have 2 window of firefox is opened, one is firefox - A, one is popup of firefox - B, when i close window A before B, all app tabs has gone. anybody has resolution for this?

Only the last closed window gets restored and if that window doesn't have the App Tabs then your App tabs are lost. Use File > Exit Firefox to close Firefox and all open windows at the same time to avoid that.

I have been having the same problem for the last few days and tried the different things that were suggested, but nothing worked. I was going to download the prior version that was working fine, but instead found Mozilla Aurora, which is actually a build before it gets to beta. I don't recommend this for the fearful, but loading this, at least as far as I can tell, brought everything back that I had previously lost, to my firefox. I could be wrong, maybe they shot out an update that I wasn't aware of before I installed this, but nonetheless, it is working now.

Well, forget my last comment. Firefox pushed out another update and now they disappear again!

Whoever the SysOp from Mozilla monitoring this forum is, please just get this bug fixed. You have a cool feature that many people like to use. Just fix the bug....

Please :)

I get this problem - but only occassionally. Kenjojones' explanation sounds highly likely (ensure you close tabbed window last). I reckon the problem in my case is download windows, popups and the like.