Check and make sure your computer's USB drivers are up to date. If you check the Device Manager screen and see an OTHER DEVICE listed as FT231X USB UART, then your system is missing the appropriate USB Serial Port driver. The driver can be downloaded directly from FTDI at the following link:

FTDI USB Serial Port Driver - WHQL Certified for Windows 7 to Windows 11 

Installation instructions for the driver can by FTDI can be found at the following link:

USB Serial Port Driver - Installation Instructions

Also, an issue can occur if you have repeatedly inserted and removed a USB device into and from a particular USB port that can cause it to stop responding. To fix this, you must uninstall the drivers for your USB Controllers on your system and reboot your PC so that they can be reinstalled automatically. Follow these steps below to carry out this process:

1. Press the Win + X keys and select Device Manager
2. In the Device Manager, double-click the Universal Serial Bus Controllers to expand it and take note of all of the USB controller drivers.
3. Right click on each of the USB Controllers and select Uninstall device (You will likely lose access to your peripherals upon selecting one of these controllers. If so, proceed to step 4 and repeat the same process until you have reinstalled all of your USB drivers).
4. Restart your computer and Windows will automatically reinstall the USB drivers you just deleted on your system.

Ensure that the system has reinstalled all of the USB Controller drivers on your system by going back into your device manager and double checking all of your drivers are back under Universal Serial Bus Controllers. The Hakko Firmware Updater should now detect your device and be able to update the firmware.