Upgrade from 8.0 to 8.1; sld_hub.vhd error

Yes you are right, Quartus archiver exactly does what you said. I wasn't aware of this option. In this case, I would try without the project\megafunctions directory, that only contains code from the same name Quartus directory, it's either superfluous or possibly wrong in most cases. It may be needed in conjunction with IP cores from previous versions sometimes.