If you are reading this, you are obviously looking at migrating Office 365 Distribution Groups to the new fancy and shiny Groups. However, if like me you are doing some testing of the migration process, then you will have created some test Distribution Groups and then ran the appropriate PowerShell script to convert it to a Group. However, as part of this testing, I found that the list of members within the Group was completely blank!

So this is an image of the DG before it was converted:

And here is an image of the DG membership before being converted:

I then ran the following PowerShell one-liner to convert the DG to a group:

Upgrade-DistributionGroup –DlIdentities dgprimary@domain.com

Here we can see the conversion has worked without issue, and in the portal, it now shows as a Group:

However… The list of members is empty!

You might be asking why… which is a good question. Originally I thought it was an issue with how O365 converts the DG to a Group, and therefore I would need to script my own method of populating the list of members within the newly converted Group. I wanted to double check with Microsoft, and I raised a ticket with O365 Support and they got back to me very quickly. So the answer is, that the list of members will automatically populate after 30-60 minutes. Which I have tested, and I can confirm that this is indeed the case. I can only think that this process is done in this manner to avoid the end users from receiving the welcome E-Mails? Anyway, I just wasn’t being patient enough in my testing. So all I will say to you is do your testing and leave it for up to 60 minutes before getting worried!