Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

When I open Firefox I get multiple Firefox.exe processes showing in my task manager. I am using Windows 7.

  • 5 replies
  • 372 have this problem
  • 4204 views
  • Last reply by ARREB

more options

When I open Firefox I get multiple Firefox.exe processes showing in my task manager. I am using Windows 7.

When I close a tab sometimes on of the processes will close also. But even with only one tab open, multiple Firefox.exe processes appear.

This starting happening in the last few days.

Chosen solution

Thank you Zachary for this response. I did verify that e10 is turned on with Multiprocess Windows set at 1/1 (default). I will monitor usage level to see if this is higher than when multiprocess is not running and if necessary the link you provided had easy to understand information on how to reset. Thanks for your help.

Read this answer in context 👍 7

All Replies (5)

more options
more options

Well said, Zachary_

more options

Chosen Solution

Thank you Zachary for this response. I did verify that e10 is turned on with Multiprocess Windows set at 1/1 (default). I will monitor usage level to see if this is higher than when multiprocess is not running and if necessary the link you provided had easy to understand information on how to reset. Thanks for your help.

more options

You may see three or more Firefox processes running.

  • one process for the main Firefox thread (user interface)
  • one or more processes for content threads set via "Options/Preferences -> General -> Performance" (dom.ipc.processCount)
  • one process for the compositor thread (Windows)

You can look at "Multiprocess Windows" to see the current multi-process state.

  • "Help -> Troubleshooting Information" -> Application Basics: Multiprocess Windows

See also:

more options

There option to limit one process does not work with the new Firefox Quantum so you will have to use and older version of Firefox and then it may actually work.

This does not work in the newest version of Firefox and will NOT run only one process. I am a 35 year computer tech with a LOT of experience. Firefox will need to patch the new Firefox Quantum to allow this option to work.