Halion One VSTs not working


I have installed Cubase 5, the Halion One Presets (but not the Orchestra trial) and patched to Cubase 5.5

However, the Halion One VSTs are missing, when I select one I get a warning and there’s no sound. Initially pretty much everything on my Cubase stream was missing (for example the presets for effects) but everything has come back apart from the MIDI voices.

I’ve installed Cubase hundreds of times before (literally - I worked in a school IT Department that used it) but this is the first time I’ve had this issue.

The only difference is this time I’m installing it on Windows 10 64 bit rather than XP or Windows 7 32 bit.

Any ideas on how I can fix this please?