Overview:

This guide provides step-by-step troubleshooting for when your Arduino isn't showing up on COM ports in Windows, particularly useful if you’re seeing errors in the Arduino IDE like: avrdude: stk500_recv(): programmer is not responding

Problem

When connecting your Arduino to your computer, it should be listed in Device Manager under Ports (COM & LPT) or Unknown Devices. If it’s not showing up, this could indicate issues with the cable, driver, or USB port configuration.

Possible Causes

• Faulty or power-only USB cable
• Driver issues (e.g., CH340 USB-to-Serial drivers)
• USB port issues
• COM port conflicts on Windows

Solution

Step 1: Check the USB Cable

Ensure you’re using a data-capable USB cable, as some cables only provide charging capabilities.

1. Try a different USB cable.
2. Test the cable with another data device if possible.

Step 2: Try a Different USB Port or Computer

1. Try different USB ports (both USB 2.0 and USB 3.0 if available).
2. Test the Arduino on a different computer to see if it’s detected there.

Step 3: Install or Reinstall CH340 Driver

If your Arduino board uses a CH340 chip (common in clone boards), you’ll need the CH340 driver.

1. Download the latest CH340 driver from here.
2. Extract the file and locate CH341SER.inf (or similar).
3. Right-click the .inf file and select Install.
4. Restart your computer, then reconnect your Arduino.

Step 4: Update USB Drivers in Device Manager

1. Open Device Manager.
2. Expand Universal Serial Bus controllers.
3. Right-click each USB controller and select Update driver.
4. Choose Search automatically for updated driver software.

Step 5: Disable USB Power Management

1. In Device Manager, expand Universal Serial Bus controllers.
2. Right-click each USB Root Hub and select Properties.
3. Go to the Power Management tab and uncheck Allow the computer to turn off this device to save power.
4. Restart your computer.

Step 6: Install USB Serial Driver with Zadig

If the Arduino still isn’t detected, try using Zadig:

1. Download and run Zadig.
2. Under Options, select List All Devices.
3. Find your Arduino device in the dropdown (it might appear as “Unknown Device”).
4. Select USB Serial (CDC) driver and click Install Driver.

Step 7: Reset COM Ports (Advanced)

If previous COM port assignments are causing conflicts, reset them:

1. Open Command Prompt as Administrator.

2. Type:
   

   set devmgr_show_nonpresent_devices=1
   

3. Open Device Manager > View > Show hidden devices.

4. Expand Ports (COM & LPT) and uninstall any greyed-out devices.

5. Restart your computer and reconnect the Arduino.

Summary

By following these steps, you should be able to resolve issues with your Arduino not showing up on COM ports in Windows. Most of the time, the problem is related to the USB cable or drivers.

Additional Resources

• Official Arduino Support
• CH340 Driver Download
• Zadig USB Driver Tool