tried rebooting? I would suggest you do.

I have this problem also - rebooted, uninstalled, including deleting all the Thunderbird entries I could find using regedit, and installed from scratch - twice - and still get the same error message. Windows 7 Pro.

About to start looking for a new e-mail client. Can't be without e-mail.

Thanks.

Ok lets get some windows basics out of the way here. Because I simply sick of the ignorance that leads to these questions.

Under windows a program does not have to have a window to be running. It starts, then puts up a windows for a user interface if and when it needs to. So when you get an error that a program is running it is.

No amount of messing with registry setting uninstalling or any of the other things people do for reason that escape me will do anything. The program is running.

Doubt me. Press Atl+Ctrl+Delete. start task manager. Locate the program in the processes tab right click and select the shut down option.

Now the program is not running. Rebooting does the same thing because to reboot it forces a shutdown of all running processes.

If repeated startup hangs occur (which is what a program starting but never getting to the point of putting up it's first window is called.) check the anti virus and firewall setting. It is quite probable that it is blocking the updates to the system necessary to startup, like checking it is the default mail program still. A very common cause of these issue are security programs that have sliders for security and folk slide them to maximum.

Past that all now. TB is gone and I'll now work thru a functional but feature-poor Windows Live Mail.

OscarL2 said

Past that all now. TB is gone and I'll now work thru a functional but feature-poor Windows Live Mail.

Yep, Microsoft officially stopped supporting it at the start of the month. Enjoy.