EMS 2010 commands: Get-DistributionGroup –ID “DistributionGroupName” | Set-DistributionGroup –ForceUpdate To “upgrade” all Distribution Groups within an Organization, the following command will do the trick: Get-DistributionGroup –ResultSize Unlimited | Set-DistributionGroup –ForceUpdate I have heard heard reports of substituting -ForceUpdate for -ForceUpgrade working as well.