I’ve set up another client on Office 365 recently and they have a couple of resource calendars – one for the Boardroom and one for the Meeting Room.

What they wanted to do that was a bit different was to have both of these calendars visible in the Apple Calendar app (or what used to be called iCal). If you add people to the resource calendar as a Delegate in Office 365, then you can view the calendar in Calendar app, but everyone gets read/write permissions, which is prone to human error and not what we wanted.

We need to have users added to the resource calendar with Reviewer level or higher permissions in order to be able to add the calendar as a delegate calendar in Calendar app. I tried adding people to the calendars at various points in the Office 365 portal and the Exchange portal, but to no avail.

What I needed to do was break out the trusty PC and tell Office 365 exactly what to do with PowerShell.

First, I logged into Office 365 as the tenant’s admin account and had a look at the existing permissions:

Get-MailboxFolderPermission -Identity boardroom:\Calendar

This gave me a list of who had what permissions:

FolderName   User         AccessRights
----------   ----         ------------
Calendar     Default      {LimitedDetails}
Calendar     Anonymous    {None}
Calendar     Kai Howells  {Editor}
Calendar     Someone Else {Editor}

As you can see, the Default user has LimitedDetails – this equates to being able to see free/busy and event titles but nothing more (I think).

I could then change the default permissions to Reviewer (see free/busy and see full event details) and also set someone (me in this example) to be the Owner so they could edit the permissions via Outlook in the future if required.

Set-MailboxFolderPermission -Identity boardroom:\Calendar -User Default -AccessRights Reviewer

Set-MailboxFolderPermission -Identity boardroom:\Calendar -User khowells -AccessRights Owner

After checking the permissions with Get-MailboxFolderPermissions, I could see it had updated:

FolderName   User         AccessRights
----------   ----         ------------
Calendar     Default      {Reviewer}
Calendar     Anonymous    {None}
Calendar     Kai Howells  {Owner}
Calendar     Someone Else {Editor}

Now that this has been done, I’m going to try adding the resource calendars back into Calendar app as a delegated calendar and it should show up with Read Only access.