Edited title as it isn't restricted to Windows 10 only. Still having no luck as of 6/20.
After some time trying to get Windows 10 to pickup the Teensy controller, I've given up. Searching the forums and the internet have not yielded any successful tips, so I'm coming to you guys.
When the LED flashes on/off, the controller will show up under 'unspecified' portion of devices/printers area as TeensyduinoRawHID - when I attempt to manually force the driver install it doesn't seem to work. I'm a computer tech and do know what I'm doing. It will list it under Device Manager as USB Composite Device - even though it's showing up differently under Devices & Printers. When I hit the button to reset it, it then redetects (w/o option to select driver) it as USB Input Device. When I use the zadig utility and try to install the WinUSB drivers it doesn't make a bit of difference either.
I was able to get the Zadig utility to pick up the 'TeensyduinoRawHID (Interface 0)' and 'TeensyduinoRawHID (Interface 1)' but installing the driver selecting either doesn't make a difference. When I reset the controller, I can choose the USB Input Device and manually install the driver, but it doesn't change anything either. Basically, my attempts to program/flash are unsuccessful because the utility will not recognize the device.