I have found out that on the the latest version of Win 10 S mode is the default. It was included on my friends new laptop. Apparently this means that all software MUST be gotten from the MS store. I do not have a Microsoft account to check, but are any versions of Vegas available there? It seems that if one wishes to keep S mode, older versions may not be able to be installed. S mode can be disabled using the MS app site, but once S mode is disabled it cannot be re-enabled. It looks as if S mode will be enabled in future Win 10 updates.
Regards,
Jerry