Description
Due to a problem in the Intel® Quartus® Prime Standard Edition Software version 20.1 and earlier, you might see this error when you have RESERVE_PIN AS_BIDIRECTIONAL assignments in the QSF file for pins that are not used by the design.
Resolution
To work around this problem, remove the RESERVE_PIN AS_BIDIRECTIONAL assignments from the QSF file if the pin is not used by the design.
This problem is fixed starting with the Intel® Quartus® Prime Standard Edition Software version 21.1.