How Microsoft Bookings Uses Scheduling Mailboxes

A New Mailbox Type to Appreciate

It’s always interesting when you discover something about an application that’s been around for a long time, like when I found some “scheduling” mailboxes in Exchange Online.

Get-EXOMailbox -Filter {RecipientTypeDetails -eq "SchedulingMailbox"} | Format-Table DisplayName

Professional Financial Advice
Office 365 for IT Pros
Sean Landy Medical Appointments

Scheduling mailboxes host the calendars used by the Microsoft Bookings app. Let’s explore how the app works and uses the scheduling mailboxes.

Note: the Microsoft Bookings app is very different to the Outlook Booking with me feature.

Controlling Access to Microsoft Bookings

Bookings is available in all Office 365 and Microsoft 365 plans unless it’s blocked at the organization level or for specific individuals. At the organization level, granular controls are available in the Microsoft 365 admin center (org settings) over different aspects of Bookings (Figure 1).

Settings for the Microsoft Bookings app
Figure 1: Settings for the Microsoft Bookings app

These settings can also be retrieved and updated using PowerShell:

Get-OrganizationConfig | Format-List Bookings*

BookingsEnabled                             : True
BookingsEnabledLastUpdateTime               : 21/07/2022 16:39:06
BookingsPaymentsEnabled                     : False
BookingsSocialSharingRestricted             : True
BookingsAddressEntryRestricted              : False
BookingsAuthEnabled                         : False
BookingsCreationOfCustomQuestionsRestricted : False
BookingsExposureOfStaffDetailsRestricted    : False
BookingsNotesEntryRestricted                : False
BookingsPhoneNumberEntryRestricted          : False
BookingsMembershipApprovalRequired          : False
BookingsSmsMicrosoftEnabled                 : True

To disable Bookings for an individual account, you remove the Microsoft Bookings app from the set of apps licensed to the account. This can be done by editing the account in the Microsoft 365 admin center, or with PowerShell. For example, here’s how to remove the Microsoft Bookings service plan (199a5c09-e0ca-4e37-8f7c-b05d533e1ea2) from an account licensed with Office 365 E3 (6fd2c87f-b296-42f0-b197-1e91e994b900):

$LicenseOptions = @{SkuId = "6fd2c87f-b296-42f0-b197-1e91e994b900"; DisabledPlans = @("199a5c09-e0ca-4e37-8f7c-b05d533e1ea2")}
Set-MgUserLicense -UserID -AddLicenses @($LicenseOptions) -RemoveLicenses @()

See this article for more details about how to use the Microsoft Graph PowerShell SDK to manage licenses for Azure AD accounts.

Creating a New Booking Page

New Booking pages (and calendars) are created through the Bookings icon in the OWA resource bar. You can block the ability to create new pages with the BookingsMailboxCreationEnabled setting in the OWA mailbox policy assigned to a mailbox. By default, the setting is True, which allows users to create new Bookings pages. Set it to False to stop this. For example:

Set-OWAMailboxPolicy -Identity "No Signatures" -BookingsMailboxCreationEnabled $False
Set-CASMailbox -Identity James.Ryan -OWAMailboxPolicy "No Signatures

Users can create a new booking page (and calendar) by selecting the Bookings icon in OWA. Oddly, people blocked from creating new pages are allowed to open the app and go through the process of entering details of the new page. It’s only when the time comes to create the page that the block descends, and they’re informed that permissions are needed to create a new booking calendar. When you think about it, the block imposed in the OWA mailbox policy refers to mailbox creation, and that’s what the block prevents. It’s just a pity that the app doesn’t stop people sooner.

When a user creates a new booking page, a background process creates a scheduling mailbox to host the calendar to store booking appointments. User mailboxes are associated with Azure AD accounts, and a first-party Microsoft enterprise app called Microsoft Substrate Management (object identifier e6ff64fa-aad6-4944-8e6c-c746c7b613a6) creates the accounts for the scheduling mailboxes. You can see this in the audit record created for a new account.

RecordType   : AzureActiveDirectory
CreationDate : 21/07/2022 13:01:58
UserIds      : ServicePrincipal_e6ff64fa-aad6-4944-8e6c-c746c7b613a6
Operations   : Add user.
AuditData    : {
                 "CreationTime": "2022-07-21T13:01:58",
                 "Id": "d007ed08-2dd8-436c-a12b-bad7df04e51e",
                 "Operation": "Add user.",
                 "OrganizationId": "a662313f-14fc-43a2-9a7a-d2e27f4f3478",
                 "RecordType": "AzureActiveDirectory",
                 "ResultStatus": "Success",
                 "UserKey": "Not Available",
                 "UserType": "System",
                 "Version": 1,
                 "Workload": "AzureActiveDirectory",
                 "ObjectId": "",
                 "UserId": "ServicePrincipal_e6ff64fa-aad6-4944-8e6c-c746c7b613a6",
                 "AzureActiveDirectoryEventType": 1,

The person who creates the new booking page becomes its administrator. Once the page is ready, the administrator can define the services to offer, their cost, and the people (staff) who can provide the service. Each user can be assigned a role for the page, such as team member (the default), supervisor, and viewer. Guest accounts are supported, but they can’t open the scheduling mailbox to view the calendar, so all their interactions are via email.

I noted that users granted the administrator role have full permission over the scheduling mailbox. However, if a user’s role is subsequently downgraded (say, to team member), they don’t lose the permission.

Making a Booking

As an example, let’s assume that the Office 365 for IT Pros writing team wanted to offer an IT consulting service. To set this up, I added the writers as staff members, defined a couple of very attractive services, and assigned different people as responsible for delivery of each service. I then enabled the page so that it’s available on the internet, and we’re open for business. Anyone can make a booking with us, even if they don’t have a Microsoft account.

When customers go to the bookings page, they see the information displayed in Figure 2 and can choose the service they want, who they want to deliver the service (or “anyone” to get a random consultant), and a time slot.

Figure 2: Scheduling an appointment

After everything is ready, the customer saves the appointment. Bookings creates a new Teams meeting for the selected date and time and sends out meeting requests to the participants. When the appointed time arrives, everyone joins the Teams meeting and the service is delivered. The only thing that’s missing is an integration with an online billing service like Stripe to collect the cash (a payment system originally offered by Microsoft is retired).

Because everything is organized around a calendar, the process of checking the calendar to see who’s occupied or available, assign time off (an appointment in the calendar), and so on is straightforward. If you can use OWA, you can use Bookings. Another good thing is that because all the bookings are stored in scheduling mailboxes, their content is indexed and discoverable.

Bookings for All

The Microsoft Bookings FAQ includes a list of ideas for how Bookings might be used. There’s lots of other good information to assimilate in the FAQ before plunging into an implementation of Bookings. I’d also spend some time playing with a couple of dummy Bookings pages to understand how the app works and how it meets the needs of different scenarios. It’s an app that’s worth checking out.

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7 Replies to “How Microsoft Bookings Uses Scheduling Mailboxes”

  1. i am an admin and i created a OwaMailboxPolicy to disable the mailbox creation for users. How even when i removed some users from these policy they are still getting the error “your admin has not enabled booking mailbox creation”

    1. It takes time for policy changes to take effect. Be patient. And if it still doesn’t work, create a support request with Microsoft to have them check things out.

  2. Hi,
    I have a user who somehow changed their role from Administrator to Team member for a booking page and was unable to change back. I tried this on my own account but the option to change role is actually grayed out, so does this means that this user is actually not a creator of this page? If that’s the case, how can i as a admin help him in changing back to administrator role?

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