Hi Painquake, This is the point in the code that when you try to move a tab left or right. However I am not sure why it would hang when moving a tab. My guess is that it is a memory issue where there are many tabs open.

I do not know why it would not close either, does this happen in Safe Mode, this will tell you if its an add on: Diagnose Firefox issues using Troubleshoot Mode

Are you trying to close a tab when this happens?

You can check for problems with the sessionstore.js file in the Firefox profile folder that store session data.

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Multiple_profile_files_created

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

You can check for problems with the places.sqlite database file in the Firefox profile folder.

• http://kb.mozillazine.org/Bookmarks_history_and_toolbar_buttons_not_working_-_Firefox
• https://support.mozilla.org/kb/Bookmarks+not+saved#w_fix-the-bookmarks-file

• Places Maintenance: https://addons.mozilla.org/firefox/addon/places-maintenance/

guigs2 said

Hi Painquake, This is the point in the code that when you try to move a tab left or right. However I am not sure why it would hang when moving a tab. My guess is that it is a memory issue where there are many tabs open. I do not know why it would not close either, does this happen in Safe Mode, this will tell you if its an add on: Diagnose Firefox issues using Troubleshoot Mode

guigs2, I normally only have two or three tabs open at a time. I don't see how it should cause memory issues but it hangs when I accidentally open two of the same tabs (mainly opening a 'new tab' blank tab) and then attempt closing the accidental duplicate. I will monitor my memory usage tonight and check for spikes in memory usage around the time the issue occurs.

-- Edit: I ran Firefox in safe-mode for about four hours before it started hanging. It gave me the script error again [entry 2077]. I kept my resource monitor open to check for abnormalities and I noticed that there's a 20% spike in memory usage at the moment the program hangs.

cor-el said

Are you trying to close a tab when this happens? You can check for problems with the sessionstore.js file in the Firefox profile folder that store session data.

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Multiple_profile_files_created

Deleting sessionstore.js will cause App Tabs and Tab Groups and open and closed (undo) tabs to get lost and you will have to recreate them (make a note or bookmark them if possible). [...]

cor-el, I have deleted the sessionstore.js and I'll keep using my browser to see if the issue persists. I will also, along with advice from another answer to monitor memory usage while using Firefox and checking if the issue follows into safe-mode.

Two changes I saw in previous solutions were to increase the session store interval and to disable hardware acceleration, but in this case may be OMTC?

guigs2 said

Two changes I saw in previous solutions were to increase the session store interval and to disable hardware acceleration, but in this case may be OMTC?

I'm not sure I understand entirely about OMTC, but I have recently disabled hardware acceleration and increased the session store interval.

Did you see any improvements with the changes that were made?

I'm sorry, but the problem still persists. Usually when two 'new tab/about:blank' tabs are open simultaneously by accident. I attempt to close one of the two and that's when the tabbrowser.xml script becomes unresponsive. I should also mention that I'm using only three to four tabs when the issues occur. (two are pinned, one active, and a new, blank tab.)

Hello, I know everyone is busy and all, but has anyone figured out a solution (or even a temporary fix) for my problem? The above solutions aren't working for my problem.

It has been about a week since my last reply and the problem is becoming worse. I have to force-close the browser (via task manager) and restart it about every half-hour to have use of the tabs.

Hi Painquake, Thank you for posting back. So far we have tried safe mode and it hangs after a few hours. And so far we have not found a solution to this issue with the work arounds we know about.

We have tried to disable extensions, disabled add ons and hardware acceleration. We have increased the script dom load time and the interval, however its after a period of time.

What we should really try to confirm if it is an extension issue it to try a new profile. Profile Manager - Create, remove or switch Firefox profiles

Have you updated your graphics card driver? Upgrade your graphics drivers to use hardware acceleration and WebGL This will confirm if it was an issue with acceleration, which is also disabled in safe mode.

guigs2 said

Hi Painquake, Thank you for posting back. So far we have tried safe mode and it hangs after a few hours. And so far we have not found a solution to this issue with the work arounds we know about. We have tried to disable extensions, disabled add ons and hardware acceleration. We have increased the script dom load time and the interval, however its after a period of time. What we should really try to confirm if it is an extension issue it to try a new profile. Profile Manager - Create, remove or switch Firefox profiles Have you updated your graphics card driver? Upgrade your graphics drivers to use hardware acceleration and WebGL This will confirm if it was an issue with acceleration, which is also disabled in safe mode.

Thank you for your prompt reply.

My graphics drivers are as up to date as they can be for my specific card, according to device manager. (the card is an ATI Mobility Radeon HD 545v,) and I'm checking with AMD/ATI's website now to be entirely sure.

I am using a new profile (as directed to in your response) and I've noticed the same problem occurs in this profile as well as a few other things. Mainly, the memory usage spikes dangerously high (for the duration of the script hanging) and the system almost overheating (the keyboard is almost too hot to touch at this moment). The memory usage and the temperature both decrease upon stopping the tabbrowser.xml script once it starts to hang.

I'm certain this is very abnormal behaviour since I have not re-added my addons (but I have added my sync data and bookmarks back) and am using only one tab.

Indeed, but in the new profile were there any updates detected for the drivers? Upgrade your graphics drivers to use hardware acceleration and WebGL

guigs2 said

Indeed, but in the new profile were there any updates detected for the drivers? Upgrade your graphics drivers to use hardware acceleration and WebGL

Using the new profile, windows update did find about 30 new updates that weren't detected previously, though unfortunately none were for drivers. I tried updating my graphics drivers manually but I am having trouble accessing AMD's website at this time.

Is it possible to access if from another computer?

guigs2 said

Is it possible to access if from another computer?

Yes, I was able to access it and transfer the installation to this computer. (I also noticed that firefox on the second computer could not replicate this issue.) There was no change in firefox's behaviour after installing and updating the driver.