This is curious because it seems logical enough that it should work. I use a similar command all the time to create new contacts and distribution groups but maybe it cannot be used to modify properties I need to uncheck all of the Require All Senders to be authenticated boxes on all the distribution groups and I dont want to do this by hand for 200 groups. So I exported the group list to a csv and cleared out everything but the display names in excel and re-saved it as a csv. Then I tried using Import-Csv groupstest.csv | ForEach { Set-DistributionGroup -identity $_.displayName -RequireSenderAuthenticationEnabled $False } However it returns: Set-DistributionGroup : Cannot bind argument to parameter 'Identity' because it is null. At line:1 char:70 + Import-Csv groupstest.csv | ForEach { Set-DistributionGroup -identity <<<< $ _.displayName -RequireSenderAuthenticationEnabled $False } Set-DistributionGroup : Cannot bind argument to parameter 'Identity' because it is null. At line:1 char:70 + Import-Csv groupstest.csv | ForEach { Set-DistributionGroup -identity <<<< $ _.displayName -RequireSenderAuthenticationEnabled $False } Anyone have any clues as to why this might not work or what I can do to achieve what I want? Thanks

If I understood correctly, you want to uncheck Require All Senders to be authenticated on the distribution lists in your environment. Well here is one liner for it Get-DistributionGroup | where {$_.RequireSenderAuthenticationEnabled -eq $True} | Set-DistributionGroup -RequireSenderAuthenticationEnabled $False