How can I find all the mailboxes that do not have a value in the ExtensionCustomAttribute1Attribute? I have tried several things with no luck. Below are a few things that I have tried:
Get-Mailbox | where {$_.ExtensionCustomAttribute1 -eq $null}
Get-Mailbox | where {$_.ExtensionCustomAttribute1 -eq {}}
Get-Mailbox | where {$_.ExtensionCustomAttribute1 -eq ""}
None of these return any results.
David Moore
David Moore