Manage OWA Signatures Using PowerShell

I recently rediscovered the Set-MailboxMessageConfiguration cmdlet ( which can be used with –SignatureHTML or –SignatureText to set a mailbox signature in OWA/ECP. There are plenty of tools out there to do this, my favourite being Exclaimer Signature Manager (, but hey we can do this for free.

I created a HTML file for each mailbox with the signature and used PowerShell to set them.

$mailboxes = Get-Mailbox
$mailboxes| foreach {$file= "C:\signatures\" + ($_.alias) + ".html"; Set-MailboxMessageConfiguration -identity $_.alias -SignatureHtml "$(Get-Content -Path $file -ReadCount 0)"}

This is useful for me as I have lots of work on with OWA only organisations at the moment. With the Exchange Server 2010 Hosting Edition (multi-tenant) providers may choose to expose Remote PowerShell so a tenant administrator could run this remotely.

I’m planning to expand this further with a simple WYSIWYG editor hosted on SharePoint to allow the Cobweb marketing department to build or upload a template, a service to pull information from AD and update both OWA and Outlook.

It would be cool to see this type functionality making it in to some SharePoint/ECP hybrid in a future Exchange release.