Can't open MS Wavetable Synth on Windows 10

midiOutOpen fails on Windows 10 when trying to open the built in wave table synth. It gives error 1 which is unspecified error.

Stackoverflow thread ( says you need to call CoInitializeEx first, but I tried that and it didn’t have any effect.

Anybody else run into this issue?

The new WinRT MIDI API can communicate with MS Wavetable Synth.

If you don’t use any of the Bluetooth functionality it’s stable.