Description
Due to a problem in the Quartus® II software version 12.0 and later, you may see this error during the Fitter if your design targets a Stratix® V desgin containing an Altera_PLL with an output clock that is unconnected.
Resolution
To work around this problem, either connect the PLL output clock to your desired logic or remove it from the instantiation of the Altera_PLL.
This problem is scheduled to be fixed in a future release of the Quartus II software.