I am having the same problem. I recently purchased the full version of Kontakt 7. Both Kontakt 6 player and the full version of Kontakt 7 worked for about a week. Now, Kontakt 6 player freezes when launching. I am in contact with Native Instruments, but they keep having me to repeat the same steps that they have already suggested. I have uninstalled the program completely, cleared the registry, as well as ran a deep virus scan, but the same results. The have even suggested to create another account in windows 11. It does opens, but errors out immediately. I really believe that it is a Native Instruments issue.
Thanks,
KG