If you don't know what is Darwin Descritor you should read this article first. To show you what it is and where you could find it here: Also you could read about Darwin Descriptor structure here . I have wrote simple C# implementation of DarwingDescriptors GUID converter. Assembly: DarwinDecriptor.dll Namespace: DarwinDecriptor .Net Framework: 4.0 Convert Darwing Descriptor GUID to System.Guid: var converter = new GuidConverter(); var encodedDarwinDescriptorGuid = "ykG^V5!!!!4!!!!MKKSk...