Web cam not detected: "Devenum.dll is either not designed to run on Vista or contains an error."

The internal web cam on my Lenovo T-400 laptop was not detected by Skype, Yawcam, or web sites that test web cams. This laptop runs Vista.

Running Skype or a few other programs would generate the following pop-up message: "Devenum.dll is either not designed to run on Vista or contains an error."

Failed efforts

Device manager showed no problems with the drivers for the integrated camera. Running sfc /scannow recognized devenum.dll as corrupt but could not repair it, even when running as administrator with a Vista system disk in the optical drive.

Devenum.dll is part of the DirectX package; some sites have reported success addressing this bug by upgrading DirectX. I tried upgrading to DirectX11to no avail.

Downloading the DirectX 11 Redistribution package allowed me to extract a different devenum.dll that should be compatible with the installed DirectX 11, but permissions restrictions prevented me from deleting or replacing the corrupt devenum.dll in Windows\System 32. Even logging in as Administrator did not help.


The successful repair involved booting into Linux with a Knoppix Live CD (which ignores Windows permissions), deleting devenum.dll, rebooting in Windows, and then copying devenum.dll from the redistribution version of the same DirectX version.  Here is the step by step:

  1. Upgrade to the current DirectX ( version 11).
  2. Create a Knoppix Live CD (a version of Linux that runs completely off the CD).
  3. Boot from the Knoppix CD (hit F12 during boot).
  4. Mount the C: drive. (Hard drives do not automatically mount in Linux.)
  5. Navigate to \Windows\System32 and deleted devenum.dll.
  6. Reboot normally into Vista.
  7. Download the DirectX Redistribution package, extracted devenum.dll, and copy to Windows\System32.

After the above, I was able to successfully use Skype and other web cam applications.

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