Stub user are unlicensed user records in Dynamics 365. Stub user can’t be logged into the system unless CRM license is assigned. While assigning a CRM license, email address in the Active Directory should match the User Name field in system user entity for the stub user to avoid a duplicate stub user creation. Stub user are very useful as “placeholder” for complex data migration scenario from CRM on-prem / other application to CRM online. Stub user concept may help customer to delay (during data migration / development phase) the license purchasing unless actual users start using the application.
Once CRM license is assigned, stub user started working as a normal user (tested in version 9.01). Please note, Stub users are completely different from interactive users and disabled users, disabled users can consume a license, and can still be a part of Office 365 or Active Directory.
When a stub user is created the Salesperson security role is assigned in a Dynamics 365 Customer Engagement instance and the Common Data Service User security role is assigned in a PowerApps environment. There is no known way to remove that role or assign a new role to any stub users. If need comes to provide additional privileges on custom or other entities that are not part of salesperson role then you will need to modify the SalesPerson security role to have those permissions.
Stub users can be created via Excel import, Create or Create Requests methods of the SDK and SSIS or other utilities. Primarily used in data migration scenario where some users are no longer within the organization however, we still need to keep track of the original owner. For stub user created by and modified by values cannot be set.
NB: During Aug- Sep ‘2018, in some minor version(22.214.171.1247) of CRM 9.0, salesperson role was not getting assigned for any new stub users. This issue was resolved in minor version (126.96.36.1998 , Oct 2018).