We have an Exchange Server 2010 running on a VMware virtual Windows Server 2008R2 x64. We also have our older Exchange 2003 server running on Windows Server 2003 x32. We are running both servers in tandem while we upgrade a number of other systems to be compatible. I have configured the replication of the public folders from 2003 to 2010 and messages are coming across fine. But posts to the 2010 server seem to take hours if not days to migrate back to the 2003 server. I don't have much experience with 2010 but everything looks to be OK. How do I troubleshoot this?