Share sub calendars in a shared mailbox

Brass Contributor

We have a shared mailbox for our servicedesk.
For different locations we have created several calendars within the default calendar, like:

- Amsterdam

- Londen

- Paris

- New York


When I assign users permissions to that calendar they don't become visible for the users.

I've assigned Review permissions on the root of the mailbox, root of the default agenda and Review and/or Editor permissions on the different location calendars.
We have done that with PowerShell:

Add-MailboxFolderPermission "servicedesk [at]\" -User 'user1 [at]' -AccessRights Reviewer
Add-MailboxFolderPermission "servicedesk [at]\Calendar\" -User 'user1 [at]' -AccessRights Reviewer
Add-MailboxFolderPermission "servicedesk [at]\Calendar\Amsterdam" -User 'user1 [at]' -AccessRights editor

But no access, whatever we try, access denied.

Also in OWA with'servicedesk [at]'/view/workweek

The only solution is when an owner enters the calendar in OWA, select the (sub)calendar, click on the three dots, select 'Sharing and permissions' and choose 'Send an sharing invitation in email'.

The user will receive an email with an invitation which can be accepted.
But isn't there any way to do this as an email administrator with PowerShell?
What is the difference in the background? I can't find it.


And another question: How do you open such a calendar in OWA or in Outlook?
You can't add anything after the default link:'servicedesk [at]'/view/workweek

Tried a lot of things, but the only way is for the user to accept the invitation and magically it pops up in 'Peoples calendars'


Thank you for any support on this matter.

4 Replies

Hi @Ron Ron,

you are having difficulties in assigning permissions to a shared mailbox calendar despite using PowerShell to grant Review and/or Editor permissions.

Following a suggestion from a, you can try creating two security groups with different permissions for the shared calendar.

One group can have Edit permissions, while the other can have Read-Only permissions. Here's the steps:

Creating Security Groups:
1. Log in to (Administrator access required).
2. Navigate to "recipients" > "groups."
3. Create a "mail-enabled security group."
4. Fill in the necessary information for the security group.
5. Add the required members.

Setting Permissions on the Shared Calendar:
1. Open the shared calendar in Outlook on the web.
2. Go to the calendar and click on "..." then choose "Sharing and permissions."
3. Enter the email of the newly created security group and click "Share."
4. Adjust the permission level to "can edit."


For your second question about opening a shared calendar, you can do so in Outlook on the web:

1. Open Outlook on the web.
2. Go to the calendar and click on "Add calendar" > "From directory."
3. Type the name of the shared calendar in the search box.
4. Click on the calendar name to add it to your view.


Please click Mark as Best Response & Like if my post helped you to solve your issue.
This will help others to find the correct solution easily. It also closes the item.

If the post was useful in other ways, please consider giving it Like.

Kindest regards,

Leon Pavesic

Hi Leon, thank you for your quick answers but they won't work.
First: It only works for users since you have to accept the invitation in your email. With an Mail Enabled Security group you will not receive this invitation.

Also your solution for my second problem doesn't work, since it is a sub-calendar, you won't find it in your addressbook, only the parent mailbox/calendar, in this case Servicedesk.
best response confirmed by Ron Ron (Brass Contributor)

It appears that you've encountered challenges with sharing sub-calendars in a shared mailbox in Exchange, particularly when using PowerShell commands. Sharing calendars in Exchange can sometimes be tricky, and there are specific steps you need to follow. Let's address your questions and provide a solution:


  1. Assign Permissions:
    • For the root calendar: Add-MailboxFolderPermission "email address removed for privacy reasons:\" -User 'email address removed for privacy reasons' -AccessRights Reviewer
    • For the default calendar: Add-MailboxFolderPermission "email address removed for privacy reasons:\Calendar\" -User 'email address removed for privacy reasons' -AccessRights Reviewer
    • For the sub-calendar (e.g., Amsterdam): Add-MailboxFolderPermission "email address removed for privacy reasons:\Calendar\Amsterdam" -User 'email address removed for privacy reasons' -AccessRights Editor
  2. Verify Permissions:
    • Use Get-MailboxFolderPermission to verify that the permissions are correctly set.





Opening Shared Calendars in OWA or Outlook:

  1. OWA (Outlook on the Web):
    • To open a shared calendar in OWA, the user can use the "Open another mailbox" feature. In the OWA interface, go to the user's profile picture, select "Open another mailbox," and enter the shared mailbox email address.
  2. Outlook Client:
    • In Outlook, users can open a shared calendar by going to "File" > "Account Settings" > "Account Settings" > "Email" > "Change" > "More Settings" > "Advanced" > "Add" and entering the shared mailbox.

Automatic Sharing without User Interaction:

To automate the sharing process without relying on users accepting invitations, you might need to use the Set-MailboxFolderPermission cmdlet along with the -SharingPermissionFlags parameter. This parameter can be set to "Delegate" to avoid the need for user interaction.






  1. Ensure that there are no conflicting permissions that might override the ones you're setting.
  2. Check for any issues with the user's mailbox, such as restrictions or configuration issues.

Remember to replace placeholders like "email address removed for privacy reasons" and "email address removed for privacy reasons" with your actual mailbox addresses. If issues persist, consider consulting the Exchange logs for more detailed error messages.

Always test such changes in a controlled environment or during non-business hours to minimize any potential impact.

If I have answered your question, please mark your post as Solved

If you like my response, please give it a Like

Appreciate your Kudos! Proud to contribute!


Thanks, I've got it working now.
I thought I did the same steps but repeating them in order gave the user access.