Managing calendar permissions on Office 365 / Exchange Online will often require you to get your hands dirty with PowerShell. The purpose of this article is to explain how to perform typical day-to-day admin tasks involving calendar permissions, using PowerShell.

Before managing permissions, you need to connect to Exchange Online through PowerShell. Once connected, you can view existing calendar permissions, add new permissions, edit existing calendar permissions, and remove calendar permissions.

Connect to Exchange Online via PowerShell

Connecting to Exchange Online via PowerShell requires just a few commands. Follow the instructions below to connect to Exchange Online from your PowerShell prompt.

  • Launch PowerShell from Workstation
  • Run the Following Four Commands in Order:
    • Set-ExecutionPolicy RemoteSigned -Force
    • $UserCredential = Get-Credential
    • $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
    • Import-PSSession $Session

NOTE: Instead of running the commands above, you can also download and run this script. After downloading, save it as a .PS1 file and run it from PowerShell using the following syntax:

.\ConnectToExchangeOnline.ps1

The above script will prompt you for O365 credentials. When prompted, supply your credentials for the O365 tenant you are trying to manage.

Viewing the Current Permissions

Before setting / updating / removing permissions from an O365 calendar, it is a good idea to see what permissions currently exist on it so they can be set back to their original permissions if you make a mistake. To list the permissions on a calendar using PowerShell, run the Get-MailboxFolderPermission command in PowerShell after you have connected to Exchange Online (see instructions above).

Get-MailboxFolderPermission -Identity john@contoso.com:\Calendar

You would obviously replace john@contoso.com with the user whose calendar permissions you want to view. If you prefer, you can pipe the output to a CSV file as well by appending | Export-CSV c:\filepath\filename.csv to the command:

Get-MailboxFolderPermission -Identity john@contoso.com:\Calendar | Export-CSV c:\filepath\filename.csv

Replace filepath with the path to the file you are creating and filename with the name you want to give the CSV file.

Removing Calendar Permissions with PowerShell in O365

Removing existing permissions from a calendar in O365 with PowerShell requires just a single command (Remove-MailboxFolderPermission). To run it, make sure you have connected to Exchange Online via PowerShell and then run the command below. In the example below, we are removing John’s access from Jen’s calendar:

Remove-MailboxFolderPermission -Identity jen@contoso.com:\Calendar -User john@contoso.com

Adding Permissions to a Calendar with PowerShell

The Add-MailboxFolderpermission PowerShell command is used to add permissions to a calendar. You can only ADD permissions to a calendar for a user if there are not already permissions configured. If you need to UPDATE permissions that already exist, you would use the Set-MailboxFolderPermission command.

To clarify, let’s use the following example:

John is a new hire at Contoso. He has not yet been given any permissions to Jen’s calendar and now needs “Reviewer” access. Since he currently has no permissions to Jen’s calendar, you would use the command below to add his permissions to Jen’s calendar:

Add-MailboxFolderPermission -Identity jen@contoso.com:\calendar -user john@contoso.com -AccessRights Reviewer

If John already had permissions (i.e. Editor, Author, etc) to Jen’s calendar, running the Add-MailboxFolderPermission command would have generated an error indicating permissions already exist. In that case, you would use the Set-MailboxFolderPermission command instead (see below).

Changing Permissions on a Calendar in O365 with PowerShell

Changing permissions that already exist on a calendar in O365 requires a different command. Instead of running the Add-MailboxFolderPermission PowerShell command, you should run the Set-MailboxFolderPermission command when you need to update pre-existing permissions.

For example, if John already has Reviewer access to Jen’s calendar, you would use the command below to change the permissions to Editor:

Set-MailboxFolderPermission -Identity jen@contoso.com:\Calendar -User john@contoso.com -AccessRights Editor

If you try to run the command above, it will fail if existing permissions are not already in place.

Available Calendar Permissions

There are 10 available roles that you can set on calendars. They are:

  • Owner.  Allows read, create, modify and delete all items and folders. Also allows manage items permissions
  • PublishingEditor.  Allows read, create, modify and delete items/subfolders.
  • Editor.  Allows read, create, modify and delete items.
  • PublishingAuthor.  Allows read, create all items/subfolders. You can modify and delete only items you create.
  • Author.  Allows create and read items; edit and delete own items.
  • NonEditingAuthor.  Allows full read access and create items. You can delete only your own items.
  • Reviewer.  Read only.
  • Contributor.  Allows create items and folders.
  • AvailabilityOnly.  Allows read free/busy information from calendar
  • LimitedDetails.  Allows view of the subject and location.
  • None.  No permissions to access folder and files.

You may use any of the above roles when setting permissions on calendars in O365 with PowerShell.

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