Hiding email address in O365 with hybird on-prem AD sync

So another gotcha when using O365 in hybird mode with on-prem sync is that you can’t hide a user’s email address [from address books and distribution lists] by using the Exhange Admin Portal. This is because the setting are made on-prem, and those defined values are simply pushing to your AAD tenant in Microsoft’s Azure cloud.

We used to be able to, from the Exchange Management Console on the on-prem server, just open the user and check a tick box to hide their address from everything. The work around isn’t much harder, it’s just buried deeper.

Open the user in your on-prem AD, and navigate the “Attribute Editor” tab.

Scroll down until you find the following attribute.

• msExchHideFromAddressLists

Setting it to “TRUE” will make the email addess hidden.

Setting it to “FALSE” or “<not set>” will make the email address visible.

After you have made the desired change to the value of the attribute, you just need to wait for [or force] your on-prem AD to re-sync with your AAD.