Fix Thonny “Couldn’t find the device automatically”

What you see

Couldn't find the device automatically.
Check the connection (making sure the device is not in bootloader mode) or choose
"Configure interpreter" in the interpreter menu (bottom-right corner of the window)
to select specific port or another interpreter.

Couldn't find the device automatically.
Check the connection (making sure the device is not in bootloader mode) or choose
"Configure interpreter" in the interpreter menu (bottom-right corner of the window)
to select specific port or another interpreter.

Quick fix — try in order

1. 1

   Install MicroPython on the board

   A new Pico has no MicroPython. Hold BOOTSEL, plug in, and copy the .uf2 from micropython.org to the RPI-RP2 drive (or use Thonny’s install button).

   Tried it
2. 2

   Select the interpreter

   Tools → Options → Interpreter → MicroPython (Raspberry Pi Pico) or MicroPython (ESP32), then pick the COM port or “Try to detect automatically”.

   Tried it
3. 3

   Do not stay in BOOTSEL mode

   If the board shows as a drive, it is in bootloader mode. Unplug and replug without holding BOOTSEL.

   Tried it
4. 4

   Close other serial programs

   Arduino IDE, another Thonny window or a browser serial tool can hold the port.

   Tried it
5. 5

   Use a data cable

   Charge-only cables give the same symptom.

   Tried it

Why it happens

Board-specific notes