Can't set com-state for "\\.\COM4

[flounder]

My student just got a new laptop to replace his old desktop. We cannot upload any sketch to the Arduino Nano. We are using the same cable as we used on the desktop. plugged directly into the only USB-A port on the laptop. We have installed the latest CH341 driver for Windows 11. How can we fix this? It works perfectly on the desktop. We are using IDE 1.8.19 (Windows Store 1.8.57.0). It is avrdude that is complaining.

[ptillisch]

Hi @flounder. This error occurs when uploading to the boards that use specific batches of the WCH CH340 USB chip. The problem only occurs when using the latest version of the CH340 driver.

The workaround for the problem is to perform a "roll back" to an older version of the driver that is compatible with these problematic "CH340" chips. I'll provide instructions you can follow to do that:

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 this forum topic to let us 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 everything will work as expected.

[flounder]

Never mind. Tracked down an earlier answer, loaded the driver from the Sparkfun site, all is good