@Nasatto
Sorry - from a .pdf file sent to me by FTDI company Customer Support Engineer David - Brilliant and thanks! - definitely solves the problem.
Sorry illustrations missing - no way of uploading file.
FTDI USB-Serial Converters – Re-installing Drivers
This document describes how to remove the drivers for all FTDI USB-Serial converters from your PC, allowing you to install the latest driver for all converters.
This has the following advantages:
Avoiding having different driver versions for different converters connected to your computer.
Avoiding conflicts between different versions of the driver which could occur when loading a new driver without un-installing the older one.
Removing COM port numbers reserved for converters no longer connected to your computer.
This procedure will un-install the driver for all devices on your system with the Vendor ID of 0403. This includes most FTDI USB-serial converters. Other products connected to your system which use the FTDI chipset with the standard FTDI / Connective Peripherals Vendor and Product IDs may also be un-installed.
This procedure is provided for information only. FTDI / Connective Peripherals accept no responsibility whatsoever for any problems or consequences resulting from its use. Users requiring further information should consult the CDM Uninstaller user guide and the installation guides provided for each OS on the FTDI website.
Step 1 - Removing the Drivers
Disconnect the USB cable of your FTDI converter(s) from the PC before running the uninstaller.
Create a folder on your desktop called CDMuninstaller. Then download the driver uninstaller from the link below and save it into the folder you created.
https://ftdichip.com/utilities/#cdm-uninstaller
Unzip the CDMUninstaller program.
Right-click on the file CDMuninstallerGUI.exe and select ‘Run as Administrator’ to ensure that the program is run with administrator privileges. You should see the window shown in Figure 1 below.
Figure 1
Leave the Vendor ID as 0403 and delete the entry 6001 in the Product ID box to leave it blank as shown in Figure 2.
Figure 2
Then click the ‘Add’ button and the window will look like Figure 3 below.
Figure 3 Shows: "VID_0403PID_" in white box,
Finally, click ‘Remove Devices’ at the bottom of the Window and the drivers for all FTDI converters will be removed. You will get one or more message boxes popping up (see Figure 4) to confirm this.
Figure 4
Once the drivers have all been uninstalled (the large text box will be blank again like Figure 1 above and the status message will be back to ‘ready’) you can close the program.
You can now proceed to Step 2.
Step 2 - Re-boot the PC
It is best to re-boot the PC at this stage before installing new drivers. You should not connect your USB-Serial converter to the PC yet.
You can now proceed to Step 3 to install the driver.
Step 3 - Installing the latest drivers
Do not connect your USB-serial converter to the PC USB port yet.
Download the file from the link below to a convenient location on your PC.
https://www.ftdichip.com/Drivers/CDM/CDM212364_Setup.zip
Un-zip the file to extract the executable installer CDM212364_Setup.exe (for example, this can be done by right-clicking the downloaded CDM212364_Setup.zip file and selecting “Extract All…” ).
Right-click on the CDM212364_Setup.exe file and select ‘Run as Administrator’ to ensure that the program is run with administrator privileges.
Windows may display the warning below. This is just to notify you that you are running a file which was downloaded from the internet. If this appears, click ‘Yes’.
Figure 5
The driver install wizard will appear a shown below. Click ‘Extract’ to proceed.
Figure 6
Windows will now extract the files provided in the setup program.
Figure 7
Click ‘Next’ to begin installing the driver.
Figure 8
You must review the license terms shown before installing the driver, and then select the appropriate radio button. By proceeding with the installation, you confirm your acceptance of these terms.
Figure 9
The wizard will then show the drivers being installed.
Figure 10
Finally, the following screen will show that the drivers were installed correctly. Both items have green ticks next to them and have status ‘Ready to use’.
Figure 11
The driver files are now on your system, and installation of any FTDI products will complete automatically using this latest driver when they are connected.
You can now connect your USB device and wait for Windows to install it as a USB Serial converter and associated USB Serial Port.
You can now proceed to Step 4 to verify the installation.
Step 4 – Verifying the Installation
Once Windows indicates that the device is installed, you should see the USB Serial Converter in Device manager. An example is shown in Figure 12. Note that for some products, the description may have been customized and so the text descriptions may not match the ones circled below exactly.
The device will show under the Universal Serial Bus Controllers section. In most cases, it will also show under Ports (COM & LPT). This depends on whether the Virtual Com Port (VCP) mode is enabled.
Figure 12
Some application software requires you to enter the COM port number assigned to your serial adapter. This can be found under the Ports (COM & LPT section). In the example in Figure 12, the adapter was assigned COM16.
