While Windows Explorer natively exposes the extensibility points as COM interfaces, .NET Framework can also be used to write some types of extensions, using the COM Interop functionality of .NET Framework. While Microsoft itself makes available extensions – such as the photo info tool – which are authored using .NET Framework, they currently recommend against writing managed shell extensions, as only one instance of the CLR (prior to version 4.0) can be loaded per-process. This behavior will cause conflicts if multiple managed add-ins, targeting different versions of the CLR, are attempted to be run simultaneously.