I just had a lot of problems with email being delivered to my Outlook 2010 really slow. The following findings are the result of my troubleshooting:
- Messages are delayed ranging from a couple of minutes up to an hour when using Outlook 2010 (using RPC or Outlook Anywhere)
- Messages are not delayed in OWA
- PowerShell shows the messages being delivered into the proper folder (Get-MailboxFolderStatistics)
- Message tracking shows that the internal transport is not delayed
- Reconnecting your Outlook will force the download of the delayed messages (CTRL+Right click the taskbar icon, selecting Connection status)
- Messages are not delayed using ActiveSync
After hitting Google with these findings it soon pointed me to the problem and also the solution.
RPC traces showed that the server couldn’t contact the clients somehow.
Install Exchange 2010 SP1 Update Rollup 3 (v3)
The installation of the Update Rollup will require a reboot of the Exchange server, but it will solve this particular issue along with other issues.
The article that pointed me in the right direction and also the source of some of the troubleshooting steps can be found right here.