stellartom

Solved my problem. Reinstalled IDE after a clean uninstall and put the Teensy in boot-loader mode. Waited for the serial port to show and was able to down load program.

I am using Tennsyduino and the USB type is Serial.

Thanks for the reply. The point I was trying to make is that I don't see the usual port on my macbook pro that I've seen in the past.

I have a data usb cable and plug in my Teensy 4.0 but can get a serial port. Meanwhile the slow blink program is running. I use the Teensy loader to load the blink fast hex file and it works. Anyone have any ideas?