Komplete Kontrol just recently started having this issue. I could not correlate the problem to anything with Native Instruments, as I had not updated anything recently and everything had been going smoothly otherwise.
I was instead focused on my hard drive, which has some files for Native Instruments on it. I can access the hard drive. When the hard drive was not connected, Komplete Kontrol could open, although no sound came from 99% of VST's. The day I got my audio interface, the hard drive started clicking but the clicking stopped when turning off other USB ports. Recently, however, I noticed a fan sound from the hard drive regardless of whether or not other USB ports were active with periodic clicking. I ran "chkdsk [] /f" in command prompt and found nothing wrong with the hard drive. When trying another hard drive used for a different computer, it also started clicking with fan noises, but even more extreme, and I couldn't access the hard drive. When putting the original hard drive on another computer, no sounds surfaced. When trying to eject the hard drive a popup shows that the hard drive is currently in use. These are the only things related to native instruments, Komplete Kontrol, or the hard drive that appears in Task Manager.
I have updated all Native Instrument VSTs, run Komplete Kontrol as administrator, turned my laptop to performance mode, and reset my computer to no avail.
I saw on another thread that it could have something to do with Komplete Kontrol having trouble accessing my hard drive. I could see this being the problem despite command prompt telling me there were no problems but I don't know how to rectify that. Do I need to get another hard drive?