OK, I havent seen this posted yet so here it goes.
I got my Oculus all setup and working one day, the next I got a error...
I thought it was a positioning issue as the program "saw" the sensor, but I just wasnt getting good coverage. After moving them all over the place and going through the setup each time I would still get the error on and off. It would work for a minute then give me the error again.
I have a corner desk I built, my computer is on the right hand edge, so to reach the sensor all the way to left side of the desk I needed a USB cable extension. I didnt need a lot, so I bought
this one from Amazon.
After researching how to setup the sensors for a couple hours I ran into
this video. In the video he explains how some extension cables, from the same company even, work, or dont work.
So to test it, I removed the extension cables, put the left sensor as far over as I could due to cable length, and the right one I put higher pointing a bit downward. It sits about a foot or so higher than the left one. For me this has worked with no trouble for a couple weeks now.
So, using the "6 ft" version of the extension USB cable gave me issues with a "weak sensor" error, the "10 ft" version of the cable works fine, even from the same manufacturer. So if your getting weak signals, or your tracking just dropping out at odd times it could be something as simple as a poor cable. The video posted above about the cable issues, has a list in the "links" section of cables that worked well for him, but use at your own risk as with anything else posted on the internet.