We've had a small number of cases come in where customers are unable to manage their Exchange 2010 environments via the Exchange Management Console. Attempts to do so result in the following error:
The following error occurred when getting user information for 'domain.com\alias':
The operations couldn't be performed because object 'domain.com\alias' couldn't be found on 'somedomaincontroller.domain.com'. It was running the command 'Get-LogonUser'."
This issue can occur when the Netbios name for your domain contains a dotted notation. Generally, Netbios domains traditionally are one word values (in the sense of what we consider as "Internet" domains, such as DOMAIN. Netbios domain names, however, supported a character set which included the period, '.' and so there are a number of organization out there who may have had their Netbios domain name set up as DOMAIN.COM, or COMPANY.DOMAIN, or any such combination that included a period or "dotted" notation.
You will need to contact us for an Interim Update that can be applied to resolve this issue. It should also be fixed in Exchange Server 2010 RU4 but at this time, we haven't gotten RU3 out the door so it will be a few months.
I've also seen this resolve issues with ActiveSync to back end E2K3 servers given the same "dotted" Netbios domain. Given that there are a number of potential components in Exchange that this could impact, if you have a dotted Netbios domain and are having some very odd problems with Exchange 2010, please give us a call (or apply RU4 if it's available when you read this).
Note: You MUST open a support incident with Microsoft Exchange Server Support. To make this as easy as possible, please refer to KB 981033 and provide the Exchange Rollup version you are currently running to get the correct fix.
EDIT: Exchange Server 2010 RU4 is now out, see http://msexchangeteam.com/archive/2010/06/17/455191.aspx. It contains the fix to resolve this issue.