We had a request to provide a list of users who have Full access to a mailbox in Office 365. The get-mailboxpermission is pretty straightforward, but the results show the Windows username as opposed to the descriptive name for the user. The following script should provide the information needed. Note that the first 3 lines connect to Microsoft Online (you will be prompted for username and password) – the last two are the magic ones. Replace “User name” with the users first and last name ie “Andy Helsby” in my case

$LiveCred = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://ps.outlook.com/powershell/ -Credential $LiveCred -Authentication Basic -AllowRedirection
Import-PSSession $Session

$userlist = Get-Mailbox "user name" | Get-MailboxPermission | Where-Object { ($_.AccessRights -eq "Fullaccess") -and ($_.IsInherited -eq $false) -and -not ($_.User -like "*nt authorityself*") }
$userlist | foreach {get-mailbox $_.user}


If I can work it out, I’ll update the script later to provide a report for all mailboxes – in the meantime this works for 1 mailbox at a time.

Funnily enough, this report didn’t actually help the reason we were asked for the report – that was because the user had issues connecting to someone else’s mailbox. It turns out that the Microsoft Online password had been changed and outlook was using the cached credentials. By removing the stored passwords in the control panel, Outlook prompted for the password and everything started working.