Thunderbird crashes after flashing grey bar with red text

Before posting, I checked some threads ("Gray bar below status bar") that looked promising, but did not work for me. I do not have the "offline.manifest" file they recommend deleting.

Running Windows XP, Mobile Intel video, just in case. No extensions installed.

I have been able to run TBird portable in that stick. But not recently. I believe the failure comes after updating to 12.

What happens is that the splash and opening screens may flash briefly, and then nothing. Thunderbird.exe does not show in the task manager. I was able to capture one of those screens, and on the gray bar below the status bar, it says the following in red text:

<!DOCTYPE overlay SYSTEM "chrome://messenger-smime/locale/msgReadSMIMEOverlay.dtd">

Will appreciate any help.

Thanks,

TN