@z31r4m I’ve done that and tested the memory, and the hardware seems to be OK. I’ve seen the same Mail crash from other Sierra users.
Services keyboard shortcuts seem to be busted.
@mjdrayton Mine, neither. Keyboard already disconnected once.
Several hard reboots later, macOS 10.12.3 finally installed. Mail crashed on first launch with internal inconsistency exception.
macOS 10.12.3 update stuck at 1 minute remaining for 45 minutes. Can’t remember the last time one of these worked normally.
Archived my old Aperture library. Given that it’s taking all morning just to empty the trash, this should greatly speed up future backups.