Set all default permissions for all calendars in O365

st00pidM$.ps1

Connect-ExchangeOnline -UserPrincipalName chris@contoso.com

$Mailboxes = Get-Mailbox -ResultSize Unlimited -Filter {(RecipientTypeDetails -eq "UserMailbox") -and (Name -ne "beheer")}

foreach($Mailbox in $Mailboxes){$Calendar = Get-Mailbox -Identity "$($Mailbox.Name)" | Get-MailboxFolderStatistics -FolderScope calendar | sort-object Date; Set-MailboxFolderPermission -identity "$($Mailbox.Name):\$($Calendar[0].Name)" -AccessRights LimitedDetails -User Default; foreach ($User in $Mailboxes){if($User -ne $Mailbox){Set-MailboxFolderPermission -identity "$($Mailbox.Name):\$($Calendar[0].Name)" -AccessRights Editor -User $($User.Name)}}}

foreach($Mailbox in $Mailboxes){$Calendar = Get-Mailbox -Identity "$($Mailbox.Name)" | Get-MailboxFolderStatistics -FolderScope calendar | sort-object Date; Set-MailboxFolderPermission -identity "$($Mailbox.Name):\$($Calendar[0].Name)" -AccessRights LimitedDetails -User Default; foreach ($User in $Mailboxes){if($User -ne $Mailbox){Add-MailboxFolderPermission -identity "$($Mailbox.Name):\$($Calendar[0].Name)" -AccessRights Editor -User $($User.Name)}}}

Updated to support Outlook for Mac who is a bit crude on the rights management.

New-DistributionGroup Rooms -RoomList -Members $Members
Add-DistributionGroupMember Rooms -Member room@domain.tld

will enable rooms in scheduling assistant in Outlook for Mac

Updated to mitigate unassigned object

Added some error handling, fallbacks and inline credentials

Oneliners ftw!

Now also available on decent OS:

https://automatica.com.au/2020/12/installing-powershell-on-macos-for-remote-administration-of-microsoft-365/

Edited auth to new spec requirements, thanks @theemstra