I started getting the 774 error yesterday. I see this is a hardware issue. Now I can hear the hard drive trying to boot up repeatedly with no luck. Sooo, I bout the WD DVR Expander drive, connected it to the HR21 and let it boot up. It recognized it, bypassed the original drive and I was back in business. Relief...until I had to move the receiver back into place. I had to cut the power. Now when my receiver boots up I get the 774 error again, even with the new WD HD expander in place. When i go into test screen and click on external it says there is no disk. Why is the receiver not booting from external hard drive? It did the first time when it intialized it. Any help?