*IF* you have the 1903 version of Win10, you need an extra step to drill into the sound control panel (Sound Settings->Sound Control Panel (in the upper right)). This is an old post talking about how to set up the Realtek as the Windows default with another Audio Interface available (Saffire and Scarlett can be interchanged).
The Realtek/Windows combo works well to playback just about everything, you just cannot record decent audio with it. On boot, *if* the Scarlett is the default device, Win10 will take control of it, and may assign it (lock it) to some internal playback, which can effectively can 'lock it out' on you. The issue is that for ASIO, only one program can control it, and if it is at a different sample rate than another program wants to use, then it will not play back. As mentioned above, setting Windows to use the Realtek as the default device, will make it leave the Scarlett alone.
Some of the issues may lie in your Windows Sound Control Panel settings.
