Macintouch has three more reports of Mail.app problems. Two of the reports sound similar to mine (crashing related to marking mail as Junk, mostly). I’ve tried one (removing the LSMMap2 file), so now I’ll try the other (reset the Junk mail filters and re-train… thought I’d tried that already, but…). Still hoping. Maybe the new security update has a fix for this? (right…)