Hi Bob, Sorry you are having problems. That is rather unusual. In a standard setup Firefox will not open multiple instances. I am afraid I can not think of a specific reason or cause for this issue. I have suggested steps that may help but it is rather generic advice rather than something targeted at your issue.

You mention Program Manger, as showing what is running, on Windows that would often be the TaskManager that is used.

Try these steps in this order,n test out what happens after each one.

1. Create a new additional Firefox profile for test purposes and try that.
   • Use keyboard shortcut Winkey & R to get the run dialogue. Then enter firefox -P Accept the location suggested. Give the profile a short name such as test-2016-001Use the profile manger to start Firefox repeatedly with the new profile.
   • See Profile Manager - Create, remove or switch Firefox profiles
2. Try a clean install. That involve deleting the program files. (Troubleshoot and diagnose Firefox problems_5-reinstall-firefox) Full details lower down.
3. Do a comprehensive malware scan. Please use all the tools suggested in the article as the tools pick up different things: Troubleshoot Firefox issues caused by malware again full details under.

Clean Install

Hello,

Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove your Firefox program files and then reinstall Firefox. This process does not remove your Firefox profile data (such as bookmarks and passwords), since that information is stored in a different location.

To do a clean reinstall of Firefox, please follow these steps: Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from mozilla.org (or choose the download for your operating system and language from this page) and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (or open the Firefox menu and click the close button ).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
   • Mac: Delete Firefox from the Applications folder.
   • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

More information about reinstalling Firefox can be found here.

WARNING: Do not use a third party uninstaller as part of this process. Doing so could permanently delete your Firefox profile data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be easily recovered unless they have been backed up to an external device! See Back up and restore information in Firefox profiles.

Malware scan

Sometimes a problem with Firefox may be a result of malware installed on your computer, that you may not be aware of.

You can try these free programs to scan for malware, which work with your existing antivirus software:

• Microsoft Safety Scanner
• MalwareBytes' Anti-Malware
• Anti-Rootkit Utility - TDSSKiller
• AdwCleaner (for more info, see this alternate AdwCleaner download page)
• Hitman Pro
• ESET Online Scanner

Microsoft Security Essentials is a good permanent antivirus for Windows 7/Vista/XP if you don't already have one. Windows 8 has antivirus built-in already.

Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Did this fix your problems? Please report back to us!

John99 said

Hi Bob, Sorry you are having problems. That is rather unusual. In a standard setup Firefox will not open multiple instances. I am afraid I can not think of a specific reason or cause for this issue. I have suggested steps that may help but it is rather generic advice rather than something targeted at your issue. You mention Program Manger, as showing what is running, on Windows that would often be the TaskManager that is used.

Maybe I am using the term instance wrong. But I have always been able to open more than one Firefox window by clicking on the Firefox Icon, and each time I do that I would see another instance of firefox32.exe running in Task Manager. (I was confusing Task Manager and Program Manager in my original post) That is what I see now too Firefox32.exe (or several copies) is running in the Task Manager but the windows will not open.

But I have tried all that Refreshing and clean install stuff. I blew away my old profile and even the entire %APPDATA%\Mozilla\ directory structure. Unless there is another place profiles are stored.

I have ran a few of the malware scanners and so far turned up nothing beyond a few "tracking cookies".

I have tried all that Refreshing and clean install stuff. I blew away my old profile and even the entire %APPDATA%\Mozilla\ directory structure. Unless there is another place profiles are stored. I have ran a few of the malware scanners and so far turned up nothing beyond a few "tracking cookies".

The clean install is about removing program files, not the profile files.

It is worth running all the anti malware tools mentioned.