hello zorblek, can you try to "Reset toolbars and controls" when you are going into safemode & see if this helps.

Unfortunately it had no effect beyond resetting my toolbars.

you're addons seem to be very common for the most part, so i don't have any hint what might be the cause. you can try disabling them all in safemode & reenable them one by one (a restart of the browser might be necessary after each step) to find out what's causing it. since safe mode runs without hardware acceleration you could also try switching that off in firefox > options > advanced > general

Huh, that's weird. Just going through the process of disabling all of my extensions and the re-enabling them one by one seems to have fixed the problem. I've got them all re-enabled again, and the problem appears to be gone. Thanks so much for your help!

Okay, it gets weirder. After I posted the last comment, I realized that I hadn't re-enabled my plugins yet. So I decided to re-enable them one by one, just as I did with the extensions. I started with Flash, and sure enough, when I restarted the browser the problem came back! So I disabled Flash, but the problem persisted. To try and make sure it wasn't just a coincidence, I disabled all of my addons again in safe mode, and then re-enabled my extensions (but not the plugins). The problem went away again. I enabled Flash and restarted and the problem was back. I disabled Flash and the problem persisted. And then I uninstalled Flash and the problem still persists.

So, to summarize: re-enabling Flash causes the problem to come back, but disabling or uninstalling Flash doesn't make the problem go away. And I am even more puzzled than I was initially.

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 > 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:
With the window for the profile folder still open, look for files named sessionstore-#.js.
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:
Firefox button > Help > Restart with Add-ons Disabled
(or Help > Restart with Add-ons Disabled, if you don't have the Firefox button)

I tried removing localstore.rdf, and that didn't help.

There's a sessionstore.js and a sessionstore.bak, but no sessionstore-#.js files. The two files that are there are slightly different sizes (47.1kb and 46.5kb, respectively). Should I try moving them?

The "Restart with Add-ons Disabled" option just restarted the browser in safe mode as usual.

I just discovered something interesting that may or may not be relevant. When I start the browser in safe mode, I don't even have to open an actual browser window. I can just close the safe mode dialog and then Firefox will start properly.

So apparently this was a bug specific to the 64-bit build of v13. A fix was released, and the problem seems to be gone. Thanks to everyone who offered suggestions!

Edit:
I should have been more specific: The 64-bit version I'm using is from the Waterfox project. When I first started using it, it was the only 64-bit build available for Windows, but now I see that's not the case any more. At any rate, the project page is here: http://waterfoxproject.org/. There's more information about the bug here: http://www.overclock.net/t/975626/waterfox-v13-pl1-6-jun-firefox-64-bit/2440. The bug seems to be a Waterfox-specific one.

zorblek, can you give me a link to where you found this info? I tried googling about a bug that causes this on the 64-bit builds but found nothing.

Which security software (firewall, anti-virus) do you have?

Does it have virtualization features that may cause problems with files not being saved properly?

I should have been more specific: The 64-bit version I'm using is from the Waterfox project. When I first started using it, it was the only 64-bit build available for Windows, but now I see that's not the case any more. At any rate, the project page is here: http://waterfoxproject.org/. There's more information about the bug here: http://www.overclock.net/t/975626/waterfox-v13-pl1-6-jun-firefox-64-bit/2440. The bug seems to be a Waterfox-specific one.

I wonder if one is supposed to be able to tell from your useragent string that it is Waterfox and not Firefox?

Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:13.0) Gecko/20120605 Firefox/13.0

For comparison, I've got (on Intel):

Mozilla/5.0 (Windows NT 6.1; WOW64; rv:13.0) Gecko/20100101 Firefox/13.0

Yeah, I don't know. I assumed the user agent string would be substantially different, but that doesn't appear to be the case. Other Firefox variants that I've tried over the years have replaced "Firefox" with the variant name (Minefield, Pale Moon, etc.). Maybe that's not common practice any more?

I kind of forgot that I was using a variant build, to be honest. This is the first time that I've ever encountered a bug that was specific to Waterfox. When I first started using it, I always suspected that any new bug I encountered was a result of using a variant build, but that never turned out to be the case, so over time I forgot about it.

I had the problem of the blank fields within the new tabs and I disabled all plug-ins to see if that would work. It didn't.

Since I have a fast computer and leave tabs on the screen I decided to go back to the old style. After a Google search I found a post by Gimkim which had me do this:

in about:config set "browser.sessionstore.restore_on_demand" to false

That worked for me. The tabs all fill on starting from Firefox and it seems to be running as I had FF12 running, which is fine for me.

Hi john181818, starting in Firefox 13 there should be a checkbox on the Tab settings for that so it can be changed in the Options dialog. Can you confirm that?

If I open a new tab there is a box in the top right corner of the browser window. The boxes do not fill, nor did they before I took the actions that were in my prior post. Ieven clicked on the individual boxes and the programs would come up, but if I opened a new tab the windows within the tab would be blank again.

So for now I am running in the configuration I stated above and it is working fine.

Thanks for checking, turns out the checkbox is scheduled to appear in Firefox 15 and your about:config fix is the only way to do it in Firefox 13.

(Also, for anyone reading, I meant in the Options dialog, not in a new blank tab.)