This install is designed to run on top of Mastercam X5. Mastercam X5 MU1 will replace the "Mastercam X5" entry in Add/Remove Programs (Programs and Features in Windows Vista and Windows 7). If X5 MU1 is uninstalled, X5 must be installed again. All personalized files in My Mcamx5 and Shared Mcamx5 are left behind, so this should not cause any loss of data. Regardless, be sure to back up your data as a precautionary measure. This product is easy to install. It will help you to manipulate Mastercam X5 in the best conditions and to create great projects.