I too am having difficulty after several crashes while attempting to upgrade to Windows 10. Each time MWB was installed causing me to reinstall MWB several times. I only have one machine but I get that error code 403. Cleverbridge did attempt to help me by purchasing a new key/ID for me but for some reason I get the same message. Has to be a registry key preventing the install. Doesn't make sense that a new Key /ID would fail first time with same error code. Haven't heard from support and unable to use premium trial so I am very unhappy with MWB. I could not find anywhere where it states this limit on installs which really concerns me. Please MWB jump in and get me up and running.