Teensy 4.0 unable to open com for reboot request

[pilot011]

I have a teensy 4.0 and i am unable to program it via USB. I programmed it before multiple time and it worked fine. I also tried another teensy 4.0 board. Tried pressing the reset button and on the teensy loader i can see it goes through the reboot process but i still cant program it.

I got the following error from the Arduino IDE

Unable to open COM4 for reboot request
Windows Error Info: Access is denied.
more ideas... https://forum.pjrc.com/threads/40632?p=126667&viewfull=1#post126667
Teensy did not respond to a USB-based request to enter program mode.
Please press the PROGRAM MODE BUTTON on your Teensy to upload your sketch.

 

[PaulStoffregen]

"Access is denied" usually means some other program has opened this COM port. Windows only allows 1 program to open the port. If something else on your PC is using it, then Arduino IDE can't also open it, which means it can't send the request to go into programming mode.

i can see it goes through the reboot process but i still cant program it.

Please remember we can't see your screen. Can you tell us specifically your eyes see? Small details matter.