Can't access public folders after upgrade to Exchange 2010

After upgrading a domain from Exchange 2003 to Exchange 2010, I cannot access the public folders from Outlook 2003 or Outlook 2007. I can access the public folders from OWA. The error message in Outlook 2003 is:

Unable to display the folder. Microsoft Office Outlook could not access the specified folder location. Could not open the item. Try again.

So far, trying again has not helped. :-P

According to the Outlook RPC diagnostic window, Outlook is connecting to the Exchange 2010 server when it tries to get the public folders.


More background before I detail the solution: the Exchange 2010 server is a new Dell R510 with onboard dual Broadcom network adapters, running Windows Server 2008 SP2 64-bit.

I worked with MS tech support to resolve this. After the tech went over the well-documented items (correct Active Directory settings, client/server encrypted communications, Best Practices Analyzer), he decided that it was a basic communications problem. He made the following changes; we're not sure which ultimately fixed it:

  • Disabled IP checksum offload
  • Disabled Receive Side Scaling
  • Disabled TCP chimney offload
  • Changed the network adapter order (Network Connections/Advanced/Advanced Settings) so the enabled adapter had precedence over the disabled adapter

Public folders now work, and other communications errors I had been seeing on the server disappeared.

If I had bothered to watch TCP traffic with Wireshark, I would have seen that TCP checksum offload wasn't working. This is something I've seen frequently with Dell servers that use Broadcom network adapters.

Take-home lesson: Broadcom adapters suck have certain issues; so you should disable acceleration or get an add-in network adapter.