Exchange Online – You can now block distribution list to be in BCC (hidden copy)

Today we all know the impact and benefits of distribution list.

Well, some time senders may want to send email to peoples and/or distribution lists in hidden copy (BCC) to avoid reply to all storm (especially with distribution list).

But you, as Exchange administrator, may want to ensure (at least certain) distribution list are always visible in the recipient list (either To or CC).

Well, you can now set your distribution list to be blocked when in BCC.

To do so, you need to use Exchange Online PowerShell (please use the ExO v2 module) and run the below command

Set-DistributionGroup –Identity <distribution list identity> -BccBlocked $true


Once done, next time somebody tries to send an email with the distribution list in BCC, a NDR (Non Delivery Receipt) will be returned with the explanation the DL is not allowed to be in BCC