Game wont download offline! Help!

I keep trying to reinstall my forza 5 game on to my xbox, however, at 49% the game stops installing, ive tried many different things but nothing works! Anyone know what to do?

Looks like a classic case of a bad disc. Have you tried installing it on a different console?

Are the rest of your games installing fine? Inspect the disc surface to see if there are any circular scratches. You may be dealing with a bad optical unit.