"side by side configuration" error message then Thunderbird looks different and creates a new, empty profile
Attempting to start Thunderbird from the taskbar today resulted in a "side by side configuration" error message. I then saw that Thunderbird in the Start menu is marked "New". Running it resulted in a new, dark-themed Thunderbird with an empty profile. I have created a third, new profile and copied all of the original profile onto it. Things seem to be working, but I wonder what happened.
Attempting to start Thunderbird from the taskbar today resulted in a "side by side configuration" error message. I then saw that Thunderbird in the Start menu is marked "New". Running it resulted in a new, dark-themed Thunderbird with an empty profile. I have created a third, new profile and copied all of the original profile onto it. Things seem to be working, but I wonder what happened.