Editor doesn't open

W10 (64-bit) user here - I have tried everything I can think of. I have ran the game with every compatibility option available by right-clicking "Troubleshoot compatibility". I have temporarily disabled the "real-time protection" setting on Windows Defender, and uninstalled McAfee. I have tried running it as an administrator. Nothing is working, and no window or errors come up either. It simply does nothing.

Also, Knytt Stories itself works perfectly, only the editor has this issue.

Out of interest, does the Knytt Stories+ editor work? Or if not that, maybe KS Level Composer? Sorry to not provide any direct solution to your issue, but maybe it can be circumvented entirely.

Tried the Stories+ editor, and it works perfectly. Thanks.