There was a recent FTDI windows driver update, although I can’t see anything that might cause devices to stop working.
FTDI - Other hardware - USB Serial Converter
Download size: 825 KB
You may need to restart your computer for this update to take effect.
Update type: Optional
FTDI Other hardware software update released in August, 2014
I believe this is FTDI version 2.12.00, release note here http://www.ftdichip.com/Drivers/CDM/CDM%202%2012%2000%20Release%20Info.rtf I guess if there was a change to nobble fakes they might not publish that info.
That update is pending in my Windows update…
Possibly due to recent news about USB hacking vulnerability they have been tightening up on USB drivers, or someone just goofed an update.
FDTI have a tool to edit the data in their devices called FT_PROG, it might be a way to recover faulty devices. It’s also a way to mess it up completely, but if it doesn’t work anyway maybe no loss. http://www.ftdichip.com/Support/Utilities.htm