Why won't UC 1.7.5.5 on PC see my Legacy 16.4.2 but UC 1.7.0 will?

I am trying to get the new release of Qmix to work (it used to work just fine) and I read that you need the new version of UC (1.7.5.5). UC 1.7.0 works just fine but when I install 1.7.5.5 it won't coect to the console and it says the "Driver is Unavailable". When I searched the forums and such, I found info that says this might be because the drivers aren't signed. However, these posts were for 1.7.4 back in December and I believe that issue has been resolved. Please help me get 1.7.5.5 to work so I can get Qmix working again. I am fine with an older version of UC but not if Qmix doesn't work with it. Thanks.