When building an application, 4D should typically know which Unlimited Desktop license to use by default. However, in some rare instances where a user may have multiple licenses for different versions or an OS upgrade has changed the Licenses folder permissions, 4D may link the incorrect Unlimited Desktop license and return a license error when building.

In this case, be sure to re-link the correct Unlimited Desktop that matches the version of 4D being used. For example, 4D v20 should be linked to the license number prefixed with 4UUD20.