I use Windows 10 and Kontakt 6 Player and was quite happy with it. When I updated to Kontakt Player 7 a few of the instruments made by Native Instruments (Hybrid Keys, Soul Sessions, Ethereal Earth) crash both the standalone and VST versions of Kontakt Player 7 every ... single ... time.
All other third party Kontakt instruments load and work fine on both versions. All my Kontakt samples are on one drive and the directories to the samples are correct. This does not make sense to me.