I use a Canopus ADV 100 frequently, as well as a Dazzle USB device. Both generally work quite dependably. However, I have encountered the same problem in several of my computers, including different operating systems. Are you using the Firewire jack or USB? Sometimes something as simple as plugging a camera into a different USB jack fixes it, sometimes when I see that black screen in the Video Capture dialog (cntl-L), I select none, and then reselect the offending camera or capture device and it works. I have found that 2 of my USB cameras can't be plugged into adjacent USB jacks. !!! There are quirks. Valerie