FWIW, I've had experience of this problem from a different angle: I've taken my server through considerable redevelopment recently, paying particular attention to allowing multiple simultaneous connections to an account. I had a similar problem where I was removing the message too early, and it *did* cause some problems (I seem to recall that one of them led to Outlook munging its cache, requiring it to be cleared). I modified the code to defer the remove until a safe time and the problems went away.
I wouldn't necessarily assume that you could rely on behaviour like this being benign, *unless* you don't support multiple simultaneous connections.
Cyrus supports multiple simultaneous connections. I have seen Cyrus work well with Outlook. I have not seen or heard that this behavior causes problems with Outlook. (Outlook shouldn't munge its cache in any case.)
I don't want to beat a dead horse, I just want to report the opposite general experience with Outlook. I've done no specific testing, but we certainly have had happy Outlook users.
Tim
