A Fusion Desktop license is tied to a single computer. If a user gets a new computer, an administrator must reset the activation before they can use Fusion Desktop on the new device.
Steps to reset a license activation:
Navigate to Admin > Users and open the User Details page for the user.
Scroll to the Desktop Apps section.
Click the Activated badge next to the assigned desktop app, and click on the Reset button in the popup dialog.
The user can now install and activate Fusion Desktop on their new computer.