add msExchHideFromAddressLists to a disabled user AD attitude.

Set-ADUser username -Add @{msExchHideFromAddressLists=”TRUE”}

wait for AD Sync…

check O365 mailbox setting

Get-Recipient [email protected] |fl HiddenfromaddresslistsEnabled

exchange (active mailbox)

Set-Mailbox -Identity [email protected] -HiddenFromAddressListsEnabled $True

more details:

https://social.msdn.microsoft.com/Forums/azure/en-US/8ef659e8-da58-4c5e-acad-2799f4b864c2/msexchhidefromaddresslists-attribute-isnt-syncing-across-to-azure?forum=WindowsAzureAD