How to grant users access to other user’s mailboxes in Office365 using PowerShell

This procedure shows how to grant users access to other user’s mailboxes in Office365 using PowerShell
How to:
*Grant a user access to a single mailbox
*Revoke the above permissions (recommended cause of action after the Administrator has finished his/her tasks)

1. Fire up PowerShell (Run As Administrator).

First make sure you have the remote signed execution policy set to true. You can do this by running PowerShell in admin mode and running:
PS> Set-ExecutionPolicy RemoteSigned

2. Next, run the following to authenticate your self and import PowerShell commands to your local session:
PS> $LiveCred = Get-Credential
(Supply credentials for MSOnline Portal: admin@company.com/Password)

3. After supplying credentials to PowerShell as $LiveCred variable, authenticate and import PowerShell commands into your local session:
PS> $Session = New-PSSession -ConfigurationName Microsoft.Exchange-ConnectionUri https://ps.outlook.com/powershell/ -Credential $LiveCred -Authentication Basic –AllowRedirection

You’re In!
PS> Import-PSSession $Session

4. For example, to grant user@company.com full access to admin@company.com, you would enter the command:
PS> Add-MailboxPermission user@company.com -User admin@company.com -AccessRights FullAccess -InheritanceType All

PS> Exit
Have the user who was granted access close/reopen Outlook and the new mailbox will be listed in their Outlook Account Tree
5. If you want to hide the user mailbox from appearing in the mailbox tree in Outlook who you just granted access, you can add the switch -AutoMapping $false

1. To Revoke access you would enter the command:
PS> Remove-MailboxPermission user@company.com -User admin@company.com -AccessRights FullAccess -InheritanceType All
Jason Coltrin
MCSE 2003:Security, CSSA
Engineer Consultant, CIO Solutions