First, if you haven't already, check out the thread linked in Antron007's post above. It gives good information that has worked for others.
Second, while the cable shows continuity at both ends, make sure that's it's data capable, and not just charging capable.
Third, I think I figured out what the issue probably is.
I just bought two Dark Apprentice LE v5 with Obsidian Sound Boards v4. I installed the newest software for the Obsidian and Emerald control/customization. I ran the installation as administrator. I turned the saber on. I connected the USB Mini cable into the PC into a 2.0 port and then proceeded to plug it into the saber. The Win10 installation recognizes the device as "Light Saber" and then ran the Ultrasaber software as admin. The saber did not connect to the software.
You need to have the Emerald/Obsidian software already running when you connect the saber. It usually won't detect the saber if it's already there, only if it's "new" i.e. plugged in after the software is running.
So, in order, probably should do on your PC so you can use the USB 2.0 ports:
0) Make sure your batteries are fully charged, or the saber is plugged into it's recharge port (if you have one). Both the software and the saber REALLY don't like it if the saber shuts off while you're changing settings/sound fonts.
1) Start Emerald/Obsidian software (run as admin).
2) Turn on Lightsaber.
3) Connect Lightsaber to Computer with USB mini cable.
That should work. Hopefully.