Description
Due to a problem in the Intel® Quartus® Prime Pro Edition Software v21.3, you may see this internal error when opening "Assignments" -> "Settings..." or "Assignments" -> "Assignment Editor".
The internal error occurs when the project includes the following assignment:
set_global_assignment -name DEVICE_MIGRATION_LIST <list of devices>
Resolution
To work around this problem, remove the following DEVICE_MIGRATION_LIST assignment from the QSF file:
set_global_assignment -name DEVICE_MIGRATION_LIST <list of devices>
This problem is scheduled to be resolved in a future release of the Intel® Quartus® Prime Pro Edition Software.