We have an addin for outlook written in extended mapi and exchange client
extensions.

When our messageStore is called into to sort a contents table, normally and
the sort is too complex say on a multivalued property we give back the
normal MAPI_E_TOO_COMPLEX error and outlook nicely gives us an error
message.

But I have recently found a problem, issue an instant search against your
say exchange folder (no problem)
Issue search against our store (no problem)
Issue search against both at the same time (view by default now groups by
Outlook Data File) we give back view too complex and then outlook literally
crashes.

If I simply ignore the sortTable and default to something sensible and don't
give back the error code outlook continues happily on its way. Anybody seen
this issue or similar ones with sorting?

Previous versions of Outlook also behave normally.