Did you hear of room lists? What is a room list?
A room list is a collection of room mailboxes. Room lists are specially marked distribution groups that you can also use the same way you use ‘regul...
Updated May 21, 2020
Version 5.0
Blog Post
mthomas1217 You could remove the room from the roomlist (although the room is still technically bookable it will just be harder to find). To do this you can use Remove-DistributionGroupMember:
Remove-DistributionGroupMember -Identity "RoomList" -Member "Room 101"
https://docs.microsoft.com/en-us/powershell/module/exchange/remove-distributiongroupmember?view=exchange-ps
As KarriS mentioned, one option is to use Set-CalendarProcessing to reject booking attempts and then use Set-Mailbox to configure a MailTip:
Set-CalendarProcessing -Identity "Room 101" -AllBookInPolicy $False -AllRequestInPolicy $False
Set-Mailbox -Identity "Room 101" -MailTip "Rooms are currently unavailable"
https://docs.microsoft.com/en-us/powershell/module/exchange/set-calendarprocessing?view=exchange-ps
You could also block book the meeting out in Outlook so it shows as unavailable and rejects all conflicts.
https://docs.microsoft.com/en-us/powershell/module/exchange/set-calendarprocessing?view=exchange-ps
You could also block book the meeting out in Outlook so it shows as unavailable and rejects all conflicts.