I'm having a problem where my USB to serial adapter will sometimes not be recognized by my laptop. It's the adapter sold by Efi Analytics with the FTDI chipset, and I'm using drivers downloaded right from their website. Sometimes I'll plug it in and it will work fine and communicate with my diypnp, but sometimes Windows doesn't recognize the device. It shows up under Device Manager as "Unknown USB Device", and if I try to update the drivers it tells me the best drivers are already installed. Also if I go into the device properties it says that "windows has stopped this device because it has reported problems. (Code 43)". Sometimes if I uninstall the driver and restart the laptop it fixes it, but then it will stop working, and then start working again at random times. I've had the same problem with two different laptops, as well as with Windows 7 and Windows 10. Is there a way in Windows 7 to force install drivers to a device and keep them installed? I have automatic Windows updates turned off as well as automatic device driver updates too.

 

Sounds like the cable itself is bad or going bad. This is the one I have and it's been good for me.

 

I don't think its the cable, I seems like an issue with Windows or the drivers. I just tried installing the drivers from the executable file on the FTDI website, and the cable works right after I install the drivers. But if I unplug it and plug it back in, it gives me the "unknown usb device" popup.