Because of a failure on Fri Nov 10,2006 we have had to do an Authoritative Restore of the System State from a Nov 2, 2006 full NTBACKUP backup. Next we had to restore the Exchange Information Store from the same backup. At this point all of our 35 Outlook clients with cached access had the email from Nov 2 - 10 but the Exchange data base did not. We found the SCANOST utility and it seems to do a pretty good job of merging the two together.
However, at each of our 3 test clients so far, when on the client, the client cannot receive email from itself. Also, a client can send email out to a remote and it will be received. However, when the remote replies the email never arrives.
When we go into ESM we can see the email trying to find a home but not able to and continually retrying to find that home.
IMHO it appears that somehow the client OST has gotten detached from Exchange. We originally thought the problem was associate with SCANOST but have come to the conclusion that it is not because it happens to test clients which have not had SCANOST applied.
This is a really complex issue and I will be happy to give you more information. We continue to work on it all day today (Sunday Nov 12).