Thsi just popped up as an issue this week so could be a Windows update, but as per most issues reported along these lines, when users open Outlook 2010 (Exchange 2007SP3 backend) they're getting a password prompt.
Saving credentials makes the issue go away (until user password changes)
We use RPC over HTTP for external users.
If I disable connect via HTTP in the outlook client, problem goes away but comes back if I enable it. Setting is use HTTP on slow lonk only but this seems to kick in regardless of location (I'm next door to the Exchange server)
Perhaps linked, staff OABs are not automatically updating each night either until a Send/Receive done.
Exchange has not been modifed for a few months so don't think it's a config issue, rather something that an update has caused.
