Solution to the RUU error 170 & 171
I successfully un-rooted my HTC One T-Mobile.
After many attempts and getting both errors 170 & 171 I finally got it to work!
I am also sure this method will work with other devices.
To get past the error 170, all I had to do was keep my phone on normally, and NOT on fastboot mode.
-Make sure you have the correct RUU for your device.
-Uninstall anything HTC related from your computer such as HTC Sync Manager and Drivers. Also delete any HTC folders from your program files.
-Make sure you leave the sdk and adb stuff that you downloaded.
-Connect your device via USB to your computer and let it recognize it. It will automatically install default drivers.
-A pop-up asking to install HTC Sync will appear, just ignore it.
-Make sure you set Fast Boot OFF on your phone, and Debugging ON.
-Leave your phone ON and run the RUU set up.
-Then follow the steps on the wizard and everything should work just fine!