Set Out Of Office With Powershell

Once upon a time, an Operations Manager emailed all the employees throughout the land and asked them to use a specific greeting for their Out Of Office message for the upcoming holiday. In the request was this statement

“(The Tinker Gnome will set the message from all of the shared mailboxes)“

Uhhhhh….. come again?

Our company employs a LOT of shared mailboxes. I don’t like setting my own Out Of Office, let alone doing it for 20+ other mailboxes that weren’t mine.

Tinker Gnomes possess a couple of traits that make us great engineers; we have a lazy side, and repetitive, monotonous tasks drive us crazy. This drives us to invent ways to do those boring, repetitive tasks for us.

This calls for a script!

$Start = "11/26/2025 14:00:00"
$End = "12/01/2025 08:00:00"
$Message = "<p>Thank you for your email. The Tinker Gnome has closed up the workshop for the Thanksgiving Holiday. The overengineering of solutions to problems nobody has will recommence Monday morning.</P><p>Have a Happy Holiday!</p>"
Connect-ExchangeOnline
Get-Mailbox -ResultSize Unlimited -RecipientTypeDetails SharedMailbox | Set-MailboxAutoReplyConfiguration -AutoReplyState Scheduled -StartTime $Start -EndTime $End -InternalMessage $Message -ExternalAudience All -ExternalMessage $Message

This script will return a list of all of the shared mailboxes in your Exchange organization and set the AutoReplyConfiguration using the values you provided. It takes under a minute to update 30 shared mailboxes. Way better than doing it manually!

Here’s what the results look like in the Exchange Admin Center for one of the shared mailbox’s Automatic Replies:

Things to keep in mind. First, you need to have the Exchange Online Powershell Module installed. Second, time must be specified in 24-hour format. And, third, the Message properties can use HTML. This is how you achieve formatting in the body of your email.

Happy scripting!