After moving to all mailboxes, public folders, and system folders from 5.5 to 2003, and tuning off all services on the 5.5 server I started getting the following events in the log. Event Type: Warning Event Source: MSExchangeIS Public Store Event Category: General Event ID: 9551 Date: 6/30/2005 Time: 1:00:03 AM User: N/A Computer: FACE Description: An error occurred while upgrading the ACL on folder [Public Folders]/RWCïBentley located on database "First Storage Group\Public Folder Store (BARNEY)". The Information Store was unable to convert the security for /O=SHUGHART, THOMSON & KILROY PC/OU=STKNT/CN=RECIPIENTS/CN=HENSC into a Windows 2000 Security Identifier. It is possible that this is caused by latency in the Active Directory Service, if so, wait until the user record is replicated to the Active Directory and attempt to access the folder (it will be upgraded in place). If the specified object does NOT get replicated to the Active Directory, use the Microsoft Exchange System Manager or the Exchange Client to update the ACL on the folder manually. The access rights in the ACE for this DN were 0x79b. After a little searching I would the following article that Said that I should have run isinteg on the 5.5 server before starting the migration. Oops, I never saw anything about this in any upgrade article I read. Anyway, it gives a solution the says it's for exchange 2000. Is it rule of thumb that if the fix worked for Exchange 2000, it will work for exchange 2003? I want to fix the problem and free up the event log of this problem. Any advice? The article # is 318549 Thanks in advance. Mike