Just an FYI - incase this happens to you
My key was working fine, but then a few days ago my key started working very sporadically. I could wiggle it and get it to work, but then sometimes in the middle of working, it would just disconnect.
This started happening more and more to where the key was almost inoperable. I looked at the key closer and noticed that it did not appear to plug all the way into the USB port. I thought this was odd, but thought maybe something was wrong with the key, like a bent contact / connection on the key.
Today the key stopped working altogether, so I removed it and was going to look to see if there indeed was a bent component of the key keeping it from making good contact or going all the way in.
I took a flashlight and shined it down in the open end of the key and SURPRISE......I found a huge piece of lint that filled the width of the USB key and was about 1/8" deep.
I took a paper clip and carefully removed the lint and the key is functioning normally now!
How did the lint get there in the first place? When going to a client's house to review 3D views, etc, I put my key in my jeans pocket. I guess over the years, it just built up.
So...check your keys for lint if you carry them in your pocket!