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


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"?

Additional System Details

This happened

A few times a week

Installed Plug-ins

  • Garmin Communicator Plug-In
  • Office Plugin for Netscape Navigator
  • Coupons, Inc. Coupon Printer DLL
  • Coupons, Inc. Coupon Printer Plugin
  • Adobe PDF Plug-In For Firefox and Netscape "9.3.2"
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • Default Plug-in
  • Shockwave Flash 10.1 r85
  • iTunes Detector Plug-in
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers
  • Npdsplay dll
  • DRM Store Netscape Plugin
  • DRM Netscape Network Object


  • User Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: Gecko/20101026 Firefox/3.6.12 GTB7.1 ( .NET CLR 3.5.30729; .NET4.0C)

More Information

schoscho 0 solutions 1 answers

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

ctse 0 solutions 1 answers

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

7Alice7 0 solutions 1 answers

Helpful Reply

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?

saido3 0 solutions 1 answers

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

BleuVII 0 solutions 1 answers

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.