Previously working ESP32s suddenly became unknown USB devices

Community General Discussion
1

It would be greatly appreciated if someone could help me sort this out.

1 Background

I’ve been successfully using these two ESP32s (ESP32 Dev Kit C V4) for a few years.

Today when I tried to upload code to one of them,using a previously working VS Code PlatformIO project, I got “A fatal error occurred: Could not open COM3, the port doesn't exist”. This worked last time I tried it on 17th September 2026. I think that was the last time I successfully used an ESP32 on this laptop (a MacBook running Windows 11).

It seems unlikely that it’s a cable fault or an ESP32 fault because I’ve tried 2 different ESP32s and 2 different data cables. Both ESP32s and the cables were known to be working recently.

I don't think it's a USB port issue because I get the same results for both the USB ports on my laptop, and those USB ports work okay with other devices (e.g. Uno R3, PicoScope).

When plugged into the USB port, the ESP32s power up and appear to run okay. One of them is definitely running okay because the code it contains has a web interface and I can access that with no problems.

What has changed since I used the ESP32 com port successfully?

  • Windows update history shows last update was on 16th September, so no update since it was last working.
  • I haven’t updated Boot Camp (Apple utility that lets you install and run Microsoft Windows natively on an Intel-based Mac) for a long time.
  • I installed the driver for a generic 8 channel 24MHz logic analyzer from https://www.saleae.com/support-assets/Saleae-Logic-Drivers.zip (I’ve uninstalled it today as part of troubleshooting the ESP32 COM port)

2 The current problem behaviour

Before I plug the ESP32 into the USB port, I see this in device manager (with show hidden devices enabled). I think the one with the red mark is the correct driver for the ESP32.

image
image437×485 111 KB

When I plug the ESP32 in I see this in device manager

image
image462×553 79.8 KB

The red line is by the new unknown device. And I get this notification:

image
image436×170 25.2 KB

When I’m repeating this test, I first right click on the unknown device in device manager and select “uninstall device”

I've tried right clicking on the "CP2102 USB to UART Bridge Controller" and selecting (at different times) both "Search automatically for drivers" and "Browse my computer for drivers" - for the driver I downloaded from https://www.silabs.com/documents/public/software/CP210x_Universal_Windows_Driver.zip. However both of those told me I've already got the correct driver e.g. for the one I downloaded.

image
image890×244 61.7 KB

2

On my windows laptop it happens occasionally that a USB device isn't recognized properly, but usually this is the result of another USB device being plugged in at the same time into the same hub. Unplugging all and re-plugging all fixes it for me.

3

Possibly, if AI is correct, that's the culprit.

image
image1083×1025 169 KB

4

Well AI has told you what to do already ?

5

Well I never! AI fixed it for me.

image
image809×949 98.4 KB

I uninstalled, as per step 1.4. Now I see the ESP32's COM port
image
image587×159 41.6 KB

I didn't have to do any of step 2.*
I can successfully upload the ESP32 via COM5 now.

6

Thanks for interacting. See post #5 for AI's solution.