If you used the latest MVVM Light version for Windows 8, you may have noticed that a couple of issues cause your app to fail the Windows App Certification Kit. It is really quite simple: By mistake, I published the debug version of the assemblies instead of the release version. This causes the certification to fail.
I already published an update on Nuget, so if you have created your application and added the DLLs using Nuget, you can update with the steps described her (scroll down to the “Updating a Package” section).
If you are not using Nuget, please download this Zip file and replace the old assemblies with the content (typically this will be in C:\Program Files (x86)\Laurent Bugnion (GalaSoft)\Mvvm Light Toolkit\Binaries\Win8).
Thanks to everyone who reported the issue and who tested the fix. As usual, any feedback is welcomed!