It's not a problem with the flash.
The problem is almost certainly a micro-switch lunder the lefthand rail of the hot shoe, that's not fully returning when the flash is removed.
That switch looks like a small button and is there to tell the camera when there is a flash mounted in the hot shoe, so that the flash won't try to open the built-in flash. The micro-switch operates by being pressed downward, when a flash or anything else is mounted in the hot shoe. When that's removed, the switch is supposed to pop back up.
The problem usually is related to the leaf spring right above the switch button, keeping it from returning fully. Turn off the camera and use either a precision screwdriver or a wooden toothpick. Gently slide the tip of that along under the leaf spring, lifting it slightly. Chances are that's all that will be needed. Test to see if the flash now pops up okay. It might be needed again after the next time you use a flash in the hot shoe.
This is a very common problem with Canon cameras. The only permanent solution I know of is to simply don't use the built-in flash. An accessory flash has a lot of advantages over the built-in anyway. One of my 7Ds has the problem and thrown Err 05 ever since it was new 4 years and about 100,000 images ago. I still haven't bothered to fix it. I just don't use the built in flash and really only know it's stuck because I've accidentally pressed the button a few times.
There are a couple other possiblities, but I'd wager the above solution will fix your camera.
P.S. You probably have a 60D, not a D60 (that's a Nikon model).
***********
Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM
