Hello! I have a problem which I find strange. Server "Old" runs Windows 2003 standard edition SP2. It is configured as a DC/GC/DNS server. Runs fileservices, print and Exchange 2003. Server "New" runs Windows 2008 R2 standard edition. Runs fileservices, print and Exchange 2010. It is also configured as a DC/GC/DNS server. I know that it is not recommended by Microsoft to run Exchange on a DC, but this is what we want. All FSMO roles are transferred to server New. This is a single domain. Everything is now moved from Old to New server. Exchange 2003 is uninstalled from Old. The next step is to remove server Old. As a first step I just turned off the GC Role on server Old. After this the "Microsoft Exchange RPC Client Access Server Service" and "Microsoft Exchange Active Directory Topology Service" stopped on server New. I had to reapply the GC role on server Old to fix the problem (because the users noticed problems in their Outlook client). The same problem appears (of course) when I Shut down server Old. I have tried to do some checking and troubleshooting. DCDiag on both servers are fine. I cannot see the problem. Server New and all clients point to server New as DNS server. Any suggestions? Regards, SindreSindre

Is New a GC? Instead of just turning off the GC role, how about just running DCPROMO to demote Old? How long did you wait? Exchange can take a few minutes to recover from a DC failure. You can reboot the Exchange server or restart the Exchange services to speed things up. -- Ed Crowley MVP "There are seldom good technological solutions to behavioral problems." . "Sindre Norderhaug" wrote in message news:d33d7618-af09-4b96-85de-520231c8cd69... Hello! I have a problem which I find strange. Server "Old" runs Windows 2003 standard edition SP2. It is configured as a DC/GC/DNS server. Runs fileservices, print and Exchange 2003. Server "New" runs Windows 2008 R2 standard edition. Runs fileservices, print and Exchange 2010. It is also configured as a DC/GC/DNS server. I know that it is not recommended by Microsoft to run Exchange on a DC, but this is what we want. All FSMO roles are transferred to server New. This is a single domain. Everything is now moved from Old to New server. Exchange 2003 is uninstalled from Old. The next step is to remove server Old. As a first step I just turned off the GC Role on server Old. After this the "Microsoft Exchange RPC Client Access Server Service" and "Microsoft Exchange Active Directory Topology Service" stopped on server New. I had to reapply the GC role on server Old to fix the problem (because the users noticed problems in their Outlook client). The same problem appears (of course) when I Shut down server Old. I have tried to do some checking and troubleshooting. DCDiag on both servers are fine. I cannot see the problem. Server New and all clients point to server New as DNS server. Any suggestions? Regards, Sindre SindreEd Crowley MVP "There are seldom good technological solutions to behavioral problems."

Hello! Thanks for your reply. Both servers are GC's, that is what makes it strange. I am just trying to be carefull before running DCPROMO on the OLD server. The OLD server once was down for an hour. The problem did not "cure itself". Exchange was "down" as far as the users were concerned. Exchange BPA does not report any critical issues. I will do some more research one evening outside working hours. I might just do a DCPROMO on the OLD server. If I should struggle I can just re-enable the OLD server as a DC and GC I guess. SindreSindre

After googling around I found suggestions to re-run "setup /preparedomain" and "setup /preparead". None of them helped either. Then I enabled IP6 again on the Windows 2008 R2 server. Restarted AD Topology service. Then waited for a new 2080 event in the application log. This solved the problem! Conclusion : Never disable IP6 on Exchange 2010 servers. In fact it is a requirement to have it enabled. Regards SindreSindre