"Dear Customer" email from Native Instruments: We are currently investigating an issue that affects our TRAKTOR KONTROL S4 Mk2, MASCHINE STUDIO, and all KOMPLETE KONTROL S-Series Mk1 hardware. Following the latest updates to Microsoft Windows 7, 8, and 10, these controllers are no longer recognized. The issue was introduced in the most recent Windows update. We are in contact with Microsoft to try to narrow down the cause and find possible solutions. Until there’s a permanent fix, you’ll need to roll Windows back to the previous version in order to keep using your hardware. We’ve created a support page showing you how to do this: Windows 10 https://support.native-instruments.com/hc/en-us/articles/360000983457 Windows 8 https://support.native-instruments.com/hc/en-us/articles/360001078378 Windows 7 https://support.native-instruments.com/hc/en-us/articles/360001061717 We apologize for any inconvenience caused, and hope to resolve the issue very soon. Best wishes, The Native Instruments team Rather than follow these instructions, I found it simpler to do a System Restore to before the update, and then turn off Automatic Updates. I sure hope they fix this soon.