Hi,
Below are the instantiations of core u3 in DE10_LITE_Golden_Top.v :
.altpll_0_c1_c1k ( ),
.altpll_1_areset_conduit_export (ARDUINO_IO[2]),
.altpll_1_locked_conduit_export (ARDUINO_IO[3])
As sstrell mentioned earlier, this is interconnection problem. I don't see ports above altpll_0_c1_c1k, altpll_1_areset_conduit_export and altpll_1_locked_conduit_export being instantiated in core.v as well as core_inst.v. May be you have to check again. There is no error at altpll_0_c1_c1k because it is not being connected yet.
Thanks,
Best regards,
Sheng
p/s: If any answer from community or Intel support are helpful, please feel free to mark as solution and give Kudos.