You may see the following error in EMC: “An error caused a change in the current set of domain controllers”. Get-DatabaseAvailabilityGroup shown below, is just one of the failing functions:

error

This is usually combined with a slow (laggy) EMC in general.

The problem can occur after having demoted Domain Controllers in your domain that EMC wants to talk to. Using Set-ADServerSettings has no effect on this problem.

To resolve the issue, simply delete the following file (the file has no extension):

C:\Users\<user>\AppData\Roaming\Microsoft\MMC\Exchange Management Console

Now your EMC is responsive again and will not show DC related errors.

Thanks to Søren Reisz for testing!