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Firefox starts on last tab but hangs and wont let me do anything else

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  • Last reply by cor-el

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When I start firefox it restores my tabs and leaves me on the last tab I left off on but I can't do anything else no new tabs and I cant scroll through my tabs. I started it in safe mode and this unresponsive script error would repeat chrome://browser/content/tabbrowser-tab.js:230 four or five times only fixing itself if I hit continue and that only happens in safe mode. If I start Firefox regularly it just hangs anybody has any idea what is causing this error and how to resolve it?

When I start firefox it restores my tabs and leaves me on the last tab I left off on but I can't do anything else no new tabs and I cant scroll through my tabs. I started it in safe mode and this unresponsive script error would repeat chrome://browser/content/tabbrowser-tab.js:230 four or five times only fixing itself if I hit continue and that only happens in safe mode. If I start Firefox regularly it just hangs anybody has any idea what is causing this error and how to resolve it?
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You can check for problems with the sessionstore.jsonlz4 file in the Firefox profile folder that stores session data.

  • delete sessionstore.jsonlz4 and sessionstore.js

When sessionstore.jsonlz4 is deleted you lose pinned tabs and open tabs and you will have to recreate them, so if necessary make a note or bookmark them. sessionstore.jsonlz4 is only present in the Firefox profile folder when Firefox is closed.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.


If you use Sync then best is to disconnect Sync temporarily during troubleshooting.

This can be caused by a problem with the places.sqlite and favicons.sqlite databases in the Firefox profile folder.

  • use "Verify Integrity" button on the "Help -> Troubleshooting Information" (about:support) page

If errors are reported with "Verify Integrity", close and restart Firefox and retry.

If "Verify Integrity" cannot repair places.sqlite, rename/remove all places.sqlite and favicons.sqlite files in the Firefox profile folder. Firefox will rebuild places.sqlite and restore the bookmarks from a recent JSON backup in the bookmarkbackups folder.

  • keep a backup copy of places.sqlite in case a new places.sqlite database has to be created

See also:


You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

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I notice you have a MySessions extension, so maybe check for issues caused by this extension and other extensions.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

  • switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
  • do NOT click the "Refresh Firefox" button on the Safe Mode start window