Hmm. The mysterious xxxx00000.xxx files are binary data files that look
kind of like the attachments that improperly-configured Exchange
servers tack onto the end of outgoing mail (winmail.dat). Maybe they
aren't related to the msg00000 problem after all.
% od -c xxx00000.xxx | head
0000000 x 237 > " 007 \r 001 006 220 \b \0 004 \0 \0 \0 \0
0000020 \0 001 \0 001 \0 001 007 220 006 \0 \b \0 \0 \0 344 004
0000040 \0 \0 \0 \0 \0 \0 350 \0 001 \b 200 007 \0 030 \0 \0
0000060 \0 I P M . M i c r o s o f t M
0000100 a i l . N o t e \0 1 \b 001 005 200 003 \0
0000120 016 \0 \0 \0 315 007 004 \0 034 \0 \t \0 + \0 / \0
0000140 001 \0 X 001 001 200 003 \0 016 \0 \0 \0 315 007 004
0000160 \0 034 \0 \t \0 , \0 002 \0 001 \0 , 001 001 \t 200
0000200 001 \0 ! \0 \0 \0 5 7 B 1 5 4 7 5 5 9
0000220 B E D 0 1 1 8 9 0 3 0 0 A 0 2 4