This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

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

What does nsAppShell: Event Window mean? Firefox won't open for me at times and I need to restart.

  • 5 tontu
  • 1187 am na jafe-jafe bii
  • 8 views
  • i mujjee tontu mooy BleuVII

more options

When I return to my computer, Firefox won't open from the "standby" mode. It gives me the message saying "Firefox is already running, but not responding" and I need to log out or restart. Firefox is not running as far as I know. When I restart, a message comes up asking if I want to close "nsAppShell: Event Window". Once I end this process, it restarts my computer and everything is fine. This is very frustrating and happens all the time. What is "nsAppShell: Event Window"?

When I return to my computer, Firefox won't open from the "standby" mode. It gives me the message saying "Firefox is already running, but not responding" and I need to log out or restart. Firefox is not running as far as I know. When I restart, a message comes up asking if I want to close "nsAppShell: Event Window". Once I end this process, it restarts my computer and everything is fine. This is very frustrating and happens all the time. What is "nsAppShell: Event Window"?

All Replies (5)

more options

What does nsAppShell: Event Window mean? Firefox won't open for me at times and I need to restart.

more options

Restart or even shut down doesn't solve the problem for me. I just cannot start Firefox. What should I do?

more options

The OP asked this question 9 months ago and 850 other people have this problem. Why hasn't Firefox Support answered this question or commented?

more options

untill now no body from supporting team can reply us to solve this problem , better uninstall Firfox browser and use another program

more options

I searched elsewhere, and found that nsAppShell is part of firefox itself, which is why other internet programs work fine.

One of common threads for everyone asking this question was AdBlock Plus. I just removed the add-on, and we'll see if that fixes the problem.

For record's sake, I also had the x3watch accountability program installed, and it often timed out at the same time as nsAppShell: Event Window. I have re-installed it. Now I just have to wait and see.