Hi Experts... I am able to run and digitally sign the dll on XP machine and even I am able to create my own sample image format. But when I tried to digitally sign the AitCodec.dll on vista and WIn7 , it fails and I am not able to see the AitEncoder in available encoder in WIC explorer . I won't be able to recognise , why dll registry entry can't be created for AIT format in the registry.