If you're migrating to Dynamics 365 and plan on moving your existing data, you'll likely run into the problem where records reference users who are no longer with the company. Ideally, you'll want to keep these references in place for historical purposes, so you'll need to find a way to create those users in your new environment. Today's blog will walk you through the steps to do just that!

The most obvious solution would be to add users in Office 365 and assign them a CRM license so they end up in CRM. The downside to this approach is that you'd potentially need a large amount of extra unused licenses to temporarily assign to these users (as the sync only happens when a license is assigned) or you'd need to add and license users in small batches, remove the licenses, and repeat until all users are added. Neither scenario is very convenient from a time or cost perspective.

A better option would be to directly create the users in CRM. Using a simple data import, you can create disabled user records which can own records and be used in look up fields.

The minimum information you'd need for each user is their first and last names as well as an email address. Set up your import to create User records, map first and last names accordingly, and map the email address to the Primary Email (internalemailaddress) field. After the import completes the users will be created in a disabled state and should receive a security role like "Salesperson," for example. Depending on how your roles are configured, you may need to assign a more appropriate role based on the data you'll be working with.

You can also confirm in the Office 365 Admin Center that you have not consumed any additional licenses.

One thing to note is that you won't be able to use these users to override fields like Created By or Modified By during data imports.

To learn more about managing Dynamics 365 users, check out these blogs:
Assigning Records to Inactive Users in Dynamics CRM
How to Tag Users and Records in Posts in Dynamics CRM
Dear Joe CRM: How do I restrict users from deleting Invoice Products?

Happy CRM'ing!