Find all Exchange mailboxes missing an Office 365 license in one line of code

Hybrid scenario – customer moved mailboxes and didn’t license them.

Pre-req of MSOL and EXO shell loaded in the same instance - super easy with my script!

$msol = get-msoluser -all | where { $_.isLicensed -eq $true }; $mbox = get-mailbox -ResultSize 5555555; Compare-Object -ReferenceObject $msol.userprincipalname -DifferenceObject $mbox.userprincipalname

Output options:

-excludedifferent

-includeequal

See more on Compare-Object here, here and here.

Sample output (neither output option shows just the delta items)

InputObject                                SideIndicator

-----------                                -------------

user1@contoso.com                               =>

user2@contoso.com                               =>

user3@contoso.com                               =>