Maybe this is some permissions problem. I have installed Spark with admin rights. And then i launch it with user and select that checkbox. Registry key with value “C:\Program Files\Spark\Spark.exe” appears in HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
I wonder why it puts startup entry to HKEY_USERS in your case. There is no kywins.exe in Spark. Maybe this is Windows appending such name in that case. But i’m clueless why this is happening for you.