Why are my Altera devices showing up as unknown devices when I do an auto-detect in the Quartus II programmer?

Description

A possible reason the Altera® devices are showing up as unknown devices when you do an auto detect when using the Quartus® II programmer is because the JTAG Server was not able to locate the parts file (<quartus_dir>/bin/pgm_parts.txt). To resolve this, make sure this file is available at this location.

If you cannot locate this file on your computer, you may need to re-install the Quartus II software.