FULL PRODUCT VERSION :
ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.0.6001]
A DESCRIPTION OF THE PROBLEM :
According to http://support.mozilla.com/en-US/kb/Firefox+hangs:
"Sometimes Java applets can cause the Firefox process to persist after exit. Try updating Java to the latest version or, if you don't need Java, disable the Java plugin by clearing the "Enable Java" checkbox in Firefox (see Using the Java plugin with Firefox for details). "
I have observed this many times.
STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Start any Java applet in Firefox 3.0.4 on Vista.
Close all browser windows.
Try to launch Firefox.
EXPECTED VERSUS ACTUAL BEHAVIOR :
On all occasions Firefox should open on the next attempt.
About one time in 20 Firefox will not open at all on the next attempt and you will see a "Close Firefox" dialog box with the message "Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system" You must then end all Firefox processes or restart the computer before Firefox will reopen.
ERROR MESSAGES/STACK TRACES THAT OCCUR :
"Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system"
This bug can be reproduced occasionally.
CUSTOMER SUBMITTED WORKAROUND :
The workaround recommended by Firefox is to disable Java.