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The selected serial port Failed to execute script esptool.

Q&A Forum › Category: ESP32 › The selected serial port Failed to execute script esptool.
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Carl Anderson asked 6 years ago

I am setting up a laptop with Win 10 Pro and an i7 CPU.  I set the laptop up as described in the tutorial.  When I  run the WiFiScan sketch I get the error “File “site-packages\serial\serialwin32.py”, line 62, in open
serial.serialutil.SerialException: could not open port ‘COM3’: WindowsError(5, ‘Access is denied.’)
Failed to execute script esptool the selected serial port Failed to execute script esptool
does not exist or your board is not connected”  I have tried my NodeMCU-32S and ESP32 DEVKIT V1 boards and get the same result with different cables and USB ports.  When I go the the device manager I only see “Intel(R) Active Management Technology – SOL (COM3).  In the past when I plugged in a ESP32 board a new COM port would appear when I had success running wifiscan.  I installed the CP210x Driver.  I also tried the CDM21228 Driver.  The wifiscan sketch is WiFIScan Arduino 1.8.7.
This report would have more information with
“Show verbose output during compilation”
option enabled in File -> Preferences.

3 Answers
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Rui Santos Staff answered 6 years ago

Hi Carl,

  1. How did you install the ESP32 add-on in your Arduino IDE? Through the boards manager?
  2. When you connect your ESP32 board to your computer, do you see a new COM port appearing? 
  3. Can you try to open the Arduino IDE as an administrator?
  4. What’s the exact serial driver that your ESP32 uses?

Thanks!

0 Vote Up Vote Down
Carl Anderson answered 6 years ago
  1. Yes, just like the tutorial.
  2. Yes, I see Com 4 now.  I found out of 7 USB cables only 2 caused com4 to appear. 

I now get the error I got before.  Copied from the IDE Messages. 
Arduino: 1.8.7 (Windows 10), Board: “NodeMCU-32S, 80MHz, 115200”
Sketch uses 599086 bytes (45%) of program storage space. Maximum is 1310720 bytes.
Global variables use 41484 bytes (12%) of dynamic memory, leaving 286196 bytes for local variables. Maximum is 327680 bytes.
esptool.py v2.3.1
Connecting…….._____….._____….._____….._____….._____….._____….._____….._____….._____….._____
A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header
A fatal error occurred: Failed to connect to ESP32: Timed out waiting for packet header
Holding the Boot button down when connecting does work but I would like a more permanent solution.
I see the same problem with 5 differnent ESP32 boards, 4 NodeMCU 32S and 1 ESP32 Devkitv1.
Carl

1 Vote Up Vote Down
Rui Santos Staff answered 6 years ago

Hello Carl,
Please take a look at this Unit: https://rntlab.com/esp32-troubleshooting-guide/
Section/heading number 4: “4. A fatal error occurred: “Failed to connect to ESP32: Timed out… Connecting…”” Holding down the BOOT button during upload will solve your problem. Regards,
Rui