Ever since I upgraded to the 1.5 RC1 version of Portable Thunderbird, I get the message "m is not a registered protocol" when I open the app. I suspect the "m" refers to the drive letter of the thumb drive that PT is running on, but I'm not sure.
If I move the Portable Thunderbird folder to the C: drive, I still get "m is not a registered protocol" when I launch it.
I've tried googling this, but haven't found a solution.
This didn't happen with 1.0.7. It only started with 1.5 RC1. Any ideas on what might be causing this or how to resolve it?