EDITED TO SAY THIS IS NOW FIXED. SEE BELOW.
I'm in a bit of a panic this morning. Yesterday I picked up a "new to me" Canon 16-35 F2.8 lens. The lens seems in very good condition. I mounted it on my 7D yesterday afternoon and it works perfectly. But this morning, I cannot remove it from the camera. I push the release button and it turns only slightly. No clicking or sound of any kind. It still works. Doing some searches, some said that screws sometime come loose on a lens mount and work their way out enough to stop the lens. Of course, I have no idea if this is it or not but I tried their suggestion of pointing the camera straight down, pushing the lens downward while turning and this has no affect.
The lens did seem tight when I put it on, but I didn't feel like I had to force it. My 50mm 1.4 also feels tight like this one did when I put it on so I didn't really think anything about it.
Does anyone have any suggestions before I call Canon or take it to a local repair facility?
I'm certain that this will be when I'll spot something exciting like a bear or mountain lion and me with a wide angle lens on the camera!!