Getting Mozilla Crash Reporter pop-up. Text is "We're Sorry Thunderbird had a problem and crashed. To help us diagnose and fix the problem, you can send us a crash report". Two boxes are checked, "Tell Mozilla about this crash so they can fix it" and "Allow Mozilla to contact me about this report". I entered my e-mail address where indicated, and clicked "Quit Thunderbird". "There was a problem submitting report" is then displayed in the crash pop-up. So, I can't submit any useful debugging information, and I can't open Thunderbird.
Full disclosure: I had a problem with my Portable Apps flash drive which I was unable to resolve (the drive cannot be read or formatted). I installed the latest Portable Apps on a new drive, installed the latest Thunderbird, then copied the folder \PortableApps\Thunderbird\Data\profile from a back-up to the same location on the new flash drive.