Just got a brand new Teensy 4.0 and 4.1. When I plug in the USB, “blink” runs and the LED flashes, but no comm port shows up. Pushing the button gives a blinking red LED (“no usb”?). On the same PC my UNO R3 works fine. A Teensy 4.1 has worked on this PC before (but I gave it away!). Tried:
several different USB cables (5)
several different PCs (3)
installing FTDI
still no comm port. Any hints?
Double check the steps here https://www.pjrc.com/teensy/first_use.html and the FAQ here https://www.pjrc.com/teensy/troubleshoot.html (the main thing to note is that it appears as a HID device only when programming the board)
I could be wrong but if I recall correctly Teensy 4.x won’t generate a COM port unless it’s running code that calls for one. Have you tried uploading code with the teensy loader application?