I was trying to download video from a digital video (DV) camcorder via Firewire (IEEE 1394) cable. This particular camcorder had no USB option. Unfortunately, the computer was not seeing the camcorder. The device wasn't showing up in Windows Explorer, and my video editing program was reporting "No DV camera detected." I ran a search and saw that others had a similar problem. I'd had this problem previously, on Windows XP, but since then I had successfully downloaded video to this computer running Windows 7. I wasn't sure why things had suddenly changed. The solution, previously, had been to boot into Ubuntu and use dvgrab. I no longer had an Ubuntu installation on this computer. My exploration of alternatives led to the possibility of creating a custom Ubuntu boot CD, using Remastersys, to include dvgrab. Before reaching that point, though, a look into Win7's Device Manager > Imaging Devices > right-click on the camcorder > Properties > General tab generated this error message:
Windows cannot start this hardware device because its configuration information (in the registry) is incomplete or damaged. (Code 19)That led to a different search. Like others, I did get the Windows sound indicating that a device had been plugged in; I just didn't get recognition of the device. I had tried uninstalling the item from Device Manager, on the theory that the camcorder should have been appearing in the "Sound, video and game controllers" section of Device Manager, not under "Imaging devices," but it came back as an imaging device again. In Device Manager > right-click on the camcorder > Properties > Driver tab > Update Driver > Search automatically, I got the reply, "The best driver software for your device is already installed." I thought maybe I could double-check that by visiting the camcorder manufacturer's website for the latest driver. But now I wondered: had I not completely uninstalled the Firewire driver in my previous try? I also recognized, at this point, that I had not included a specific reference to "Code 19" (above) in my previous search, so I tried again. A page at About.com listed a number of troubleshooting steps. One that I had not tried and that seemed especially relevant was to delete the UpperFilters and LowerFilters values in the registry via Start > type Regedit > HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class, as indicated in an About.com tutorial. At that location, as indicated by a table showing device class GUIDs, it seemed I was looking for the GUID for either "Imaging Devices" (which was where Device Manager was actually showing the camcorder) or for "Sound, video and game controllers" (which was where the other source, above, said the camcorder should have been appearing). The GUID table did not have precisely those same options. Instead, it had entries for Video Adapters, for the IEEE 1394 host controller, for Cameras and Scanners, and for Audio and Video Devices. I decided to start with the IEEE 1394 host controller. The table said the GUID for that was 6BDD1FC1-810F-11D0-BEC7-08002BE2092F. I looked for that number under the Class registry location (above). I found it and clicked on it. The tutorial said that I should now see UpperFilters and LowerFilters values. I didn't. In that case, the tutorial said, this wasn't the right solution for me. Just in case, I tried clicking on the Properties item under that GUID. This produced an error:
Error Opening KeySo, hmm, that could be either part of the same problem, or yet another problem. I backed up and tried checking the GUID for Cameras and Scanners. According to the table (above), that GUID was 6BDD1FC6-810F-11D0-BEC7-08002BE2092F, almost the same as the one just examined. Under that one, I did see a LowerFilters entry, but nothing for UpperFilters. The tutorial said that was OK, just delete whichever one did appear there. So I clicked on the LowerFilters item and hit the Delete key. I got a warning asking me to confirm, and noting that this could cause system instability. I went with it and then, as advised, I closed down everything and rebooted. Before rebooting, just for good measure, I right-clicked on the item in Device Manager that had the yellow triangle and black exclamation mark next to it -- that is, the camcorder entry under Imaging Devices (above) -- and selected uninstall. On reboot, that returned there; but this time, its Properties reported, "This device is working properly." I tried downloading video from the camcorder again. This time it worked.
Properties cannot be opened.
An error is preventing this key from being opened.
Details: Access is denied.
So the solution, for me, this time, was to delete the UpperFilters and/or LowerFilters keys in the registry and perhaps also to try again at deleting that erring entry in Device Manager, and then reboot.
With that solution in place, it became unnecessary for me to pursue other leads I had identified. These included another guide to delete the necessary registry keys in Windows XP and Vista, complete with a script to do it automatically; a guide to delete a different registry key -- in Vista, but apparently also applicable to Windows 7, with an alternate eHow presentation.