If your computer suddenly stops recognizing your FTDI USB to serial adapter, or if you see a yellow exclamation mark next to FT232R USB UART in Device Manager, you are dealing with a common driver configuration issue.
This guide outlines how to troubleshoot and fix this problem on Windows 11, 10, and 7.
Step 1: Perform a Quick Hardware Check
Before modifying any software files, rule out physical connection issues:
- Connect Directly: Unplug your FTDI adapter and plug it directly into your computer. Avoid unpowered USB hubs.
- Switch Ports: Try using a different USB port (preferably a USB 2.0 or USB 3.0 port directly on your motherboard or laptop chassis).
- Test the Hardware: If possible, connect the adapter to another PC to ensure the cable itself is not physically damaged.
Step 2: Install the Official FTDI VCP Driver Manually
For most devices like Arduino boards, 3D printers, or network routers, you need the Virtual COM Port (VCP) driver. This driver forces Windows to recognize the USB connection as a standard COM port.
- Go to the official FTDI website.
- Navigate to the VCP Drivers section.
- Locate the currently supported VCP drivers table and download the version corresponding to your Windows operating system (32-bit or 64-bit).
- Extract the downloaded
.zip file to a folder on your Desktop.
- Open the extracted folder, right-click on
ftdiport.inf, and select Install (on Windows 11, you may need to click Show more options -> Install).
- Grant administrator permission when prompted by User Account Control.
- Next, right-click on
ftdibus.inf in the same folder and select Install.
- Replug your FTDI USB adapter.
To verify, open Device Manager (Press Windows Key + X and select Device Manager), then expand the Ports (COM & LPT) category. You should now see your device listed as USB Serial Port (COMx) without any warning symbols.
Step 3: Update Drivers Automatically via Windows Update
If you prefer Windows to handle the driver search:
- Open Device Manager.
- Right-click the flagged FT232R USB UART device and select Update driver.
- Choose Search automatically for drivers.
- If Windows does not find one, click Search for updated drivers on Windows Update to check the optional updates section.
Frequently Asked Questions
Why does Device Manager show "This device cannot start (Code 10)"?
This code indicates that Windows loaded an incorrect, corrupted, or generic driver state. To fix it:
- Open Device Manager.
- Right-click the FTDI device and select Uninstall device.
- Check the box for Attempt to remove the driver for this device and click Uninstall.
- Restart your computer and perform a clean driver installation using the steps in Step 2.
VCP vs. D2XX Drivers: Which one do I need?
- VCP (Virtual COM Port): The standard choice. It emulates a traditional serial port and is compatible with almost all standard terminal software.
- D2XX: Used exclusively by specialized proprietary applications that communicate directly with the FTDI chip via custom APIs. Unless your specific hardware instructions demand D2XX, stick with VCP.
