# Windows – “Thunderbird is already running” error every time I try to start Thunderbird, even if it is not running

emailthunderbirdwindows

I cannot open Thunderbird. The process isn't running, but when I click on the icon, I get the the following error:

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

I've tried the following:

• Deleting parent.lock
• Uninstalling Thunderbird
• Uninstalling Firefox
• Running Thunderbird in software "safe mode" and Windows safe mode

What can I do to fix this problem?

The problem looks more serious than expected. I do not see any Mail folder in my profile at C:\Users\your-username\AppData\Mozilla\Thunderbird. I think I lost my email.