Supporting Mailto links if Thunderbird is already open
I configured mailto links to go to Thunderbird Portable. This works fine if Thunderbird is closed. However if Thunderbird is already open, then I get an error message when clicking on an email link: 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.
My registry settings for the mailto command --
Key: HKEY_CLASSES_ROOT\mailto\shell\open\command to:
Value: "r:\ThunderbirdPortable\ThunderbirdPortable.exe" "%1"