Gets to about 81% then says disk access error can't install, any ideas?

It is something with Galaxy. Using "Verify/Repair" option usually works.

I had disk access error with other games installed through Galaxy, so it is very unlikely that it is 8-bit Hordes fault. :) I had it too while installing this game and verify/repair worked. The only issue I had was that 8-bit Armies failed to detect Hordes installed and kept fantasy armies blocked, but reinstalling 8-bit Armies fixed it and now I can play all four armies in both games.

I did indeed trouble shoot it myself and the verify button worked, it took a few tries though! keep up the great work gog! Ps: Get the warlords series on this! or at least warlords III darklords rising! :D