Warning (169174): The Reserve All Unused Pins setting has not been specified

Try changing it to a different value and see if the warning message changes.

Are you really sure you want the unused outputs to drive ground? If you do, then you must make sure to define all inputs and outputs in your top-level design that exist on the schematic, even if your HDL does not use them.

If you use this setting and do not define all inputs that are used on the FPGA, then the FPGA will drive those inputs (those that are on bidrectional pins anyway) and you will damage any external devices attempting to drive those FPGA inputs high.

Its rarely a good idea to use that setting.

Cheers,

Dave