When trying to launch the Diagnostic Console, it will then display the following error: Failed to connect to <<SERVERNAME>> Could not open server registry key.
<<SERVERNAME>> = Exchange Server the Diagnostic Console is trying to connect to.
1. Click Start | Run
2. Type regedit and connect remotely to the registry using the Spotlight on Messaging service account, use run-as on regedit if not presently logged on as that account.
3. If successful or unsuccessful, proceed to the next step.
4. Ensure the Service account is a member of the Local Administrators group on all Exchange Servers.
5. Ensure the Service account has Exchange View-Only permission on the Organization.
6. Check that there are not any old cached credentials on the Exchange Server, specifically the service account used.
7. Logon to the Exchange Server locally with the Administrator account
8. Click Start | Run
9. Type control keymgr.dll
10. Remove all existing cached credentials