One of our administrators was facing some weird errors in the EMC and came to me for support. He showed me the errors bellow, and i knew them because this is quite common in Exchange 2010.
In our case this issue was caused by a recent demotion of a Domain Controller, and however the configuration of Exchange 2010 was updated the errors occurred.

Errors:

An error caused a change in the current set of domain controllers. It was running the command ‘Get-Mailbox – Identity ” -ReadFromDomainController’.
An error caused a change in the current set of domain controllers. It was running the command ‘Get-Recipient -PropertySet ConsoleLargeSet -ResultSize ’1000′ -SortBy DisplayName -RecipientType ‘DynamicDistributionGroup’,’UserMailbox’,’MailContact’,’MailUser’,’MailUniversalDistributionGroup’,’
MailUniversalSecurityGroup’,’MailNonUniversalGroup”.

Solution:

1. Close the EMC
2. Go to c:\users\<the user with problem>\appdata\roaming\microsoft\mmc\ and delete or rename the file Exchange Management Console.
3. After this restart the EMC ( no reboot of the server is necessary ).



ENJOY.

And if you encounter any problems feel free to comment / contact me.