To open a new window, you must close the current Thunderbird process, or restart your system. Thunderbird is already running but is not responding.

John.I cannot give other details that it has become very annoying I tried everything the internet suggested but it continues to wreak havoc. To open a new window, you must first close the existing Firefox process, or restart your system. Firefox is already running but is not responding. I keep having a problem with this error message. Firefox crashes or does not - how to fix.Error message 'Firefox is already running but is not responding' - how to fix.The problem and the solutions are explained in the articles: It is also worth watching for the plugincontainer.exe. Search the firefox process firefox.exe and kill him with for example the Task Manager. I had a computer scientist to try everything, and we cannot on it to open it.

I installed FF on my new computer, Windows 7 Toshiba, I get the message Firefox is already running but is not responding. I have message handler Firefox is already running but is not responding.

Mozilla firefox not responding error