Comment 25 for bug 12097

7 years later, I have this bug in Hirsute ! (or at least the same symptoms: I click on a mailto link and a window named “close Thunderbird” appears, with the message :
“Thunderbird is already running, but is not responding. To use Thunderbird, you must first close the existing Thunderbird process, restart your device, or use a different profile.”

Firefox version 89.0 (64bits)
Thunderbird version 78.8.1 (64 bits)