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Why is my browser closing overnight?

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I'm very busy at nights and usually when I am about to go to sleep I keep my laptop on. I am using a MacBook Pro running Mac OS X El Capitan. When I am about to go to sleep I use the software "insomnia" on my Mac so it basically disables lid sleep or idle sleep. At night I am downloading some important files that are very large and I let it download overnight but when I wake up and open my laptop Firefox is closed and its just shows me the desktop screen. The download is not there. Is there any software or add ons to prevent Firefox from automatically closing overnight?

Thanks for the help. Much appreciated.

I'm very busy at nights and usually when I am about to go to sleep I keep my laptop on. I am using a MacBook Pro running Mac OS X El Capitan. When I am about to go to sleep I use the software "insomnia" on my Mac so it basically disables lid sleep or idle sleep. At night I am downloading some important files that are very large and I let it download overnight but when I wake up and open my laptop Firefox is closed and its just shows me the desktop screen. The download is not there. Is there any software or add ons to prevent Firefox from automatically closing overnight? Thanks for the help. Much appreciated.

Chosen solution

I can't think of any feature in Firefox that would close the browser automatically. Maybe an add-on or an external program is doing it?

You can view, disable, and often configure or remove nonessential extensions on the Add-ons page. Either:

  • Command+Shift+a (Windows: Ctrl+Shift+a)
  • "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then cast a critical eye over the list on the right side. All extensions are optional. If in doubt, disable the ones you won't need overnight.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.


External software is a little harder to track down. I'm not familiar with MacOS X so this is based more on Windows.

It's possible for the OS and possibly other programs to close Firefox by sending "close window" commands to each open window. If you have multiple tabs open, normally there would be a warning about closing multiple tabs; there may be an exception for the last window if you have Firefox set to restore the previous session at startup, then you might not get a warning closing the last window.

What programs might do that? Utility programs that clean up private data, maintenance programs that do disk stuff, backup programs... who knows.

If you are not leaving multiple windows open with multiple tabs in them, try that and see whether Firefox is still closed. To minimize bandwidth, you can open the internal blank page about:blank in those windows (type or paste that "address" into the address bar and press Return to load it; you can bookmark it for faster access, then Command+click the bookmark to load it in more tabs).

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All Replies (4)

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¡Hola!

It might be that something is causing your Firefox to crash overnight.

Please paste the 10 top most lines of the about:crashes page for us to take a look.

¡Gracias!

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I don't think its crashing because it says no crash reports have been submitted. I think it might be like a specific amount of time for it to close.

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Suluhisho teule

I can't think of any feature in Firefox that would close the browser automatically. Maybe an add-on or an external program is doing it?

You can view, disable, and often configure or remove nonessential extensions on the Add-ons page. Either:

  • Command+Shift+a (Windows: Ctrl+Shift+a)
  • "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then cast a critical eye over the list on the right side. All extensions are optional. If in doubt, disable the ones you won't need overnight.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.


External software is a little harder to track down. I'm not familiar with MacOS X so this is based more on Windows.

It's possible for the OS and possibly other programs to close Firefox by sending "close window" commands to each open window. If you have multiple tabs open, normally there would be a warning about closing multiple tabs; there may be an exception for the last window if you have Firefox set to restore the previous session at startup, then you might not get a warning closing the last window.

What programs might do that? Utility programs that clean up private data, maintenance programs that do disk stuff, backup programs... who knows.

If you are not leaving multiple windows open with multiple tabs in them, try that and see whether Firefox is still closed. To minimize bandwidth, you can open the internal blank page about:blank in those windows (type or paste that "address" into the address bar and press Return to load it; you can bookmark it for faster access, then Command+click the bookmark to load it in more tabs).

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I'll try to disable to extensions and try tonight. Thanks for all the help and suggestions.