Remove Shared Mailbox in Outlook using Windows PowerShell Open Windows PowerShell as an Administrator and run the following commands Set-ExecutionPolicy RemoteSigned $UserCredential = Get-Credential Login with PRIMARYmailbox Credentials $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection Import-PSSession $Session -DisableNameChecking Replace <SHAREDMailbox> and <PRIMARYMailbox> with respective email [...]