Microsoft 365 is as popular as ever.

Microsoft 365 is growing every day. Thankfully, Microsoft continues to enable functionality via their admin centers. If you’re spending time as a Microsoft 365 administrator and not leveraging PowerShell, you’ll save yourself hundreds of hours by learning. The community is strong, and learning resources are plentiful. But it is nice when something can be done via admin.microsoft.com or entra.microsoft.com (aka Azure Active Directory).

External Users were added to the directory, but your list will not upload when trying to add them as Members.

What gives? Well, Microsoft being Microsoft (or me just skipping over documentation too quickly), the Guest email addresses (i.e., [email protected]) will not be the Guest’s Principal Name in AD. This would be more obvious to the folks with more AD experience than those less Microsoft-centric in their experiences. Thankfully Microsoft follows structured formatting when creating the Principle Names.

[email protected] becomes guest_gmail.com#EXT#@contoso.onmicrosoft.com

A quick spreadsheet =SPLIT and =CONCATENATE, and we’re in business for our bulk .csv upload the file. It becomes obvious AD would do this, and the error clearly states the issue, but the cloud-centric world just has usernames. An external User in a Google Group for example would be the email address. At first, I thought it might just be a provisioning delay before the Directory user could be added to a Group. Perhaps this post will save someone a bit of time!