Cannot change a distribution group that contains more than 1,800 members by using ECP in OWA in an Exchange Server 2010 environment

Applies to: Exchange Server 2010 Service Pack 3Exchange Server 2010 EnterpriseExchange Server 2010 Standard

Symptoms


Consider the following scenario:
  • You sign in to Outlook Web App (OWA) and then open Exchange Control Panel (ECP) in a Microsoft Exchange Server 2010 environment.
  • You open a large distribution group that contains more than 1,800 recipients, and then you expand the Membership tab.
  • You add or remove a recipient in the members list, and then click Save.
In this scenario, you receive the following error message:
The recipient "MailboxName" is already a member of the group "GroupName".

Cause


This issue occurs because of a logic defect in the ECP code. Specifically, ECP calls only the Update-DistributionGroupMember cmdlet instead of calling the Add-DistributionGroupMember or Remove-DistributionGroupMember cmdlet for large distribution groups.

Resolution


To resolve this issue, install the following update rollup:
2866475 Description of Update Rollup 2 for Exchange Server 2010 SP3

Status


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.