I have a Hypertech 30029 for my 05 GMC. When I first programmed it a few monthes ago, it locked up 5 times while uploadeing before it finally went. Yesterday, I changed my tires to 285 BFG muds, and reprogrammed to suit The hypertech lost connection 23 times before it went. Every time, it locked up at 63% uploaded. I was really starting to worry it wasn't gonna work and i would have to tow it. But Now im afraid to use the computer again as I'm worried that it will leave me dissabled. Has anyone else encountered this? I'm expecting hypertech to return my call tommorow sometime, but I think im gonna loose the hypertech and go fo a predator.

have changed program many times, with no problems. see what hypertech says.

I've had the same thing happen. The dealer's vendor was programming it for me the first time--they had to download the factory programming from GMC w/ a Tech II. For some reason with the door closed--yes the dome light was off with it open--it wrote the program, but not on the first try.