Firefox: Browser Will Not Start Up


Troubleshooting Mozilla Firefox Browser

NOTE: Firefox may fail to load after installing or updating the McAfee SiteAdvisor Firefox extension. To correct this error, you can either open your browser in Safe Mode, or uninstall the extension.

Browser Tech Support:  1-800-935-0537


Profile Errors:

  • Profile in use - You must end the browser process or restart your system to unlock the profile. This error occurs because your profile is inaccessible.
  • Firefox is already running but is not responding - You must first close the existing Firefox process, or restart your computer. This error occurs because your profile is locked.


Windows Users:

General: If your browser will not start, restart your computer in Safe Mode and disable all add-ons. Then re-enable add ons one by one, restarting Firefox each time. This way you can see if it is a faulty add-on causing your browser to be unable to start.

Windows Vista: End the process "xpicleanup" process, if found. Open Internet Explorer, and browse to C:\Users\[your username]\AppData\Local\VirtualStore\Program Files\Mozilla Firefox and delete the file "xpicleanup.dat."

Windows XP or earlier: Open Internet Explorer and browse to C:\Documents and Settings\[your username]\Application Data\Mozilla and delete the file "xpicleanup.dat."

"The program must close to allow a previous installation attempt to complete. Please restart."If you receive this error, and you have already tried restarting your computer, exit Firefox completely. Press CTRL+ALT+Delete to open the Task Manager.

"Error opening file for writing..." (only for Vista users)
If you receive this error, it is probably because you are not logged onto your computer as an administrator. To work around this, you should be able to right-click the Firefox icon and choose "Run As Administrator."

"JS_DHashTableOperate could not be located in the dynamic link library js3250.dll" (only for Firefox 2.0 users)
If you receive this error, this usually means there was a flaw in the Mozilla Firefox installation when upgrading to 2.0 (most likely because some Firefox processes were open during the upgrade). You will have to uninstall Firefox completely, making sure that the firefox.exe process is not running, and reinstall the program.


Mac Users:

If you try to open Firefox, and a browser does not appear, quit the process by pressing Cmd+Q and opening ~/Library/Application Support/Firefox/Profiles/.default/. You will have to remove the "localstore.rdf" file and restart Firefox. Any toolbar customizations or window placement changes you have made will be lost.


Linux Users:

If you used "sudo" mode to install Firefox and the browser fails to run as a normal user, check the ownership of "$HOME/.mozilla" and the subdirectories. The ownership of these may be set to "root:root" and you will need to execute "chown -R : $HOME/.mozilla" at the command line to get Firefox to work. (This will most likely only occur when using Firefox 1.0) Each user will have to execute this command for the browser to work.


Referenced from: Mozilla Firefox

7/12/2017 1:01:38 PM