https://www.olimex.com/dev/pdf/ARM/JTAG/Repair%20Procedure%20for%20OpenOcd-Rev.%20G%20drivers.pdf

Repair procedure for ARM-USB-OCD drivers

1.   Uninstalling ARM-USB-OCD drivers
-------------------------------------
1.1. Connect your programmer/debugger to your computer, open Device Manager
     and uninstall the drivers for ARM-USB-OCD.
1.2. After you have uninstalled ARM-USB-TINY driver from Device Manager,
     disconnect the programmer from your computer.
1.3. Now you should download FTClean.exe from here:
     http://www.ftdichip.com/Support/Utilities/FTClean.zip.
1.4. After download is complete extract the "*.zip" file, open folder FTClean,
     and run FTClean.exe
1.5. Ror VID (Hex) select "Other". And after that fill the first box with 15ba
     and "PID (Hex)" with 0004.
1.6. Press "Clean System" button.  Make sure that all FTDI devices are
     disconnected. (My require administrator privileges).

2. Re-installing the ARM-USB-OCD driver
---------------------------------------
2.1 Connect the programmer/debugger to the computer.
2.2 When prompted, browse to the C:\gccfd\DRIVERS\ARM-USB-OCD-DRIVER
    directory and install. (A different driver is required for OpenOCD
    0.4.0.  That driver is available from the olimex.com web site).