> ## Documentation Index
> Fetch the complete documentation index at: https://support.taltech.com/llms.txt
> Use this file to discover all available pages before exploring further.

# COM port from adapter no longer works after upgrading to Windows 11

> Find out why an RS232-to-USB adapter stopped working after a Windows 11 upgrade, and whether to replace it or update its driver.

If you have an RS232-to-USB adapter with a **Prolific chipset** that stopped working after upgrading to Windows 11, you will likely need to buy a new one. Adapters with *older* Prolific chipsets are not compatible with Windows 11, but *newer* ones should work.

If your adapter uses an **FTDI chipset**, it should continue to work, although you may need to update the driver software. To do this:

1. Open the Windows Device Manager (on Windows 10 & 11, right-click on the Start button and select “Device Manager”).
2. Expand the “Ports (COM & LPT)” section by clicking on the small arrow next to it.
3. Right-click on the COM port for your RS232-to-USB adapter and select “Update Driver”.
4. Reboot your PC after updating the driver software.

For more info on the Device Manager and COM port troubleshooting, see [Identify your device’s COM port with Device Manager](https://support.taltech.com/winwedge/identify-com-port.md).

This article is from TALtech, makers of WinWedge and other Windows software
for collecting instrument data.


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