Firefox opens with tiny blank window.

Question

I recently stopped using the session manager feature of the Tab Mix Plus extension so I could use Firefox 13's Tabs on Demand feature. Since I made the switch, I've been having a strange problem. Usually (not always, but maybe 4 times out of 5) when I start Firefox, instead of displaying a normal browser window it displays a tiny blank window. The window is just wide enough for an icon and the min/max/close buttons. There are no toolbars or chrome of any kind (not even the Firefox menu). The window is resizable, but resizing it doesn't reveal any contents.
I can fix this by starting Firefox in Safe Mode (which properly restores all of my open tabs) and then restarting the browser, after which point it works normally until I have to restart it again. So nearly every time I open the browser I first have to open it in Safe Mode and then restart it.
I've tried disabling Tab Mix Plus (which I still use for other features), but that didn't help. I'm not sure which of my other extensions might be causing the problem. Has anyone else seen this issue? I'm stumped about what could be causing it. Thanks in advance for any help!

Answer 1

I was about to say earlier: Are you sure that solved your problem? As disabling then re-enabling your addons shouldn't have solved this problem so easily.
I really doubt Flash is causing this. You could have a corrupted localstore.rdf file. Or it might be possible there's a problem with your session restore files. There might be extra copies that shouldn't be there causing this.
Go to '''Firefox button <img src=https://support.mozilla.org/media/uploads/images/2012-03-27-09-22-48-1204f1.png> > Help > Troubleshooting Information''' then click on the '''Show Folder''' button.
Once the window for the profile folder opens, close Firefox. Then look for a file named localstore.rdf in that folder and delete it. Restart Firefox and see if the problem stays gone. That file remembers the size & position of your Firefox windows. Maybe it needed to be deleting manually. The Safe Mode "Reset Toolbars" choice madperson told you to use was supposed to delete this file and I think it did since you lost the organization of your toolbar icons. But this is just to be sure.
'''If that doesn't work, try Step #2:'''
<br> With the window for the profile folder still open, look for files named sessionstore-#.js.
<br> Ex. sessionstore-2.js, sessionstore-3.js, etc.
If you see these files, temporarily move them to the Recycle Bin in case we need them later. The file with the highest number attached should be your latest, most recent backup of your tabs & windows. Ex. sessionstore-8.js vs. sessionstore-9.js
To compare, tell us what size your original sessionstore.js file is & what the size is of the highest numbered copy of the same file is. Also I'm wondering how many tabs you have restored when you use Firefox Safe Mode? You can guess/estimate.
If no numbered sessionstore files are found, I'm pretty sure it's a addon responsible. One of them could have a new bug since Firefox 13 changed some code.
Try disabling add-ons this way instead of with Firefox Safe Mode:
<br> '''Firefox button <img src=https://support.mozilla.org/media/uploads/images/2012-03-27-09-22-48-1204f1.png> > Help > Restart with Add-ons Disabled'''
<br> (or Help > Restart with Add-ons Disabled, if you don't have the Firefox button)