I manage a tenant with around 300 distribution lists (DLs) and mail-enabled Microsoft 365 groups. I've already generated a report detailing the owners and member counts for each group to pinpoint areas for improvement. However, I'm now looking to assess the actual usage of these groups. Specifically, I want to find out if the DLs are actively being utilized and what purpose these M365 groups serve—I'm guessing they might mostly be for shared calendars or emails. I want to avoid manually tracing messages for each group in the exchange admin center, and I'm having difficulty figuring out how to do this through PowerShell. Any suggestions for tools or resources would be greatly appreciated! If there's a better method for determining their usage or purpose, I'd love to hear that as well. Thanks!
4 Answers
A simple workaround could be to send out a mail merge to the distribution group asking if they're still in use. Let them know that if no response is received, you plan on deleting the group soon. Sadly, that's often a fantasy solution in many organizations, but it's worth considering. In the meantime, it might help to restrict who can create groups to prevent further clutter.
You can also achieve this using the Start-HistoricalSearch command in PowerShell. Just note that it only goes back 90 days. Here's a link to the documentation: [Start-HistoricalSearch](https://learn.microsoft.com/en-us/powershell/module/exchangepowershell/start-historicalsearch?view=exchange-ps). That should help you get started!
You can use PowerShell for this task! Check out the Get-MessageTraceV2 command. Keep in mind to chunk requests in 10-day increments and then reassemble the data. I had success using AI tools like GitHub Copilot to generate a script for this too. Here's a good resource that helped me: [Get-MessageTraceV2](https://learn.microsoft.com/en-us/powershell/module/exchangepowershell/get-messagetracev2?view=exchange-ps). Also, be aware that you might want to modify your output to fit your needs in Excel afterwards.
You can definitely gather usage reports through the Exchange Admin Center, but you'll need to do some manual filtering. Just keep in mind that their data usually goes back about three months when you're looking for usage stats.
Yeah, I ran into issues with some AI outputs as well—some reports turned out inaccurate. Manual reports worked better for me when I needed to confirm activity.