How do I prevent WCH driver update Win11?

[bambuino]

I am getting fairly peeved that MSWindows constantly updates the the drivers from WCH for the CH340 USB-Serial adapter breakout boards. The 2014 drivers are what works for the Nano and everything I have. The 2023 drivers don't work.

Does anyone know of the fix that stops this update from happening in Windows?

[ptillisch]

Hi @bambuino. Windows has a special driver "roll back" feature that allows you to install an older version of a driver when there is a problem with the latest version. When you use this "roll back" procedure to install the older version, Windows is smart enough to understand that it should not later automatically update the driver back to the bad newer version again.

The many Arduino forum members affected by the incompatibility between the latest version of the WCH CH340 driver and certain sketchy batches of "CH340" chips have found that this roll back procedure is an effective solution. I'll provide instructions you can follow to roll back to the compatible version of the driver:

1. Click the following link to download the previous version of the driver from the chip manufacturer's website:
   https://www.wch-ic.com/downloads/file/65.html?time=2023-03-16%2022:57:59
2. Wait for the download to finish.
3. Run the downloaded CH341SER.EXE file.
4. A "User Account Control" dialog may now appear asking "Do you want to allow this app to make changes to your device?". Click the "Yes" button.
5. A "DriverSetup(X64)" dialog will open. Click the "INSTALL" button in the dialog.
6. Wait for the driver installation to finish, as indicated by the appearance of a "Driver install success!" dialog.
7. Click the "OK" button in the "Driver install success!" dialog.
   The dialog will close.
8. Click the X icon at the top right of the "DriverSetup(X64)" dialog
   The dialog will close.
9. Close Arduino IDE if it is running.
10. Connect the Arduino board to your computer with a USB cable.
11. Open the Windows Device Manager.
12. Select View > Devices by type from the Device Manager menus.
13. Open the "View" menu.
14. If there is a ✓ to the left of the "Show hidden devices" menu item, click on "Show hidden devices" to disable it.
15. Open the "Ports (COM & LPT)" section of the Device Manager tree.
16. You should see a port identified as "USB-SERIAL CH340 (COMn)" under the "Ports (COM & LPT)" section (where "COMn" is some serial port e.g., COM4). Double click on that item.
    The "USB-SERIAL CH340 (COMn) Properties" dialog will open.
17. Select the "Driver" tab of the "USB-SERIAL CH340 (COMn) Properties" dialog.
18. You will see a "Roll Back Driver" button in the dialog. If it is not clickable, perform the following instructions:
    1. Click the "Update driver" button.
       An "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog will open.
    2. Click on "Search automatically for drivers" in the "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog.
    3. You should now see the driver installation wizard update the driver. Wait for the update to finish, as indicated by the message "Windows has successfully updated your drivers" in the dialog.
       It is possible you will instead see the message "The best drivers are already installed". If so, please stop following the instructions here and reply on the forum thread to let me know. I'll provide alternative instructions you can follow.
    4. Click the "Close" button in the "Update Drivers Device - USB-SERIAL CH340 (COMn)" dialog.
       The dialog will close.
19. Click the "Roll Back Driver" button in the "USB-SERIAL CH340 (COMn) Properties" dialog.
    The "Driver Package rollback" dialog will open.
20. Click the radio button next to "My apps don't work with this driver" in the "Driver Package rollback" dialog .
21. Click the "Yes" button.
    The "Driver Package rollback" dialog will close.
22. Click the "Close" button in the "USB-SERIAL CH340 (COMn) Properties" dialog.

Now start Arduino IDE again and repeat whatever you were doing before when you encountered that error before. Hopefully this time you will not encounter that "can't set com-state" error during the sketch upload.