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Firefox opens with huge number of tabs whose access brings Firefox to a halt

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  • 1 has this problem
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  • Last reply by cor-el

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When Firefox is launched on my Mac desktop, it takes a long time to display a browser window, and the window is filled with innumerable tabs whose origins I can't understand. I have tried many of the remedies suggested for dealing with too many tabs, and none seem to work. I trashed the Firefox application and the folder /User/Library/Application_Support/Firefox, restarted the Mac, and Firefox works well for a while, but when I do a Google Search the browser window is suddenly populated with huge numbers of tabs that seem similar to what I have seen in past occasions, and Firefox stalls. Are there some other files containing a record of all these tabs that I can delete, to stop this from happening?

I can't "Refresh Firefox", because Firefox is unusable at the point when the problem occurs.

When Firefox is launched on my Mac desktop, it takes a long time to display a browser window, and the window is filled with innumerable tabs whose origins I can't understand. I have tried many of the remedies suggested for dealing with too many tabs, and none seem to work. I trashed the Firefox application and the folder /User/Library/Application_Support/Firefox, restarted the Mac, and Firefox works well for a while, but when I do a Google Search the browser window is suddenly populated with huge numbers of tabs that seem similar to what I have seen in past occasions, and Firefox stalls. Are there some other files containing a record of all these tabs that I can delete, to stop this from happening? I can't "Refresh Firefox", because Firefox is unusable at the point when the problem occurs.

Chosen solution

You can check that those pages aren't set as multiple homepages.

You can check the homepage setting.

Firefox supports multiple homepages separated by '|' (pipe) symbols.


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.

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Chosen Solution

You can check that those pages aren't set as multiple homepages.

You can check the homepage setting.

Firefox supports multiple homepages separated by '|' (pipe) symbols.


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.