Share sub calendars in a shared mailbox

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.

Troubleshooting:

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.