OK, I pulled my hair out for almost 2-days. I'd install the Moto USB driver ware on my PC (Moto Device Mgr V2.5.4) and when I'd connect my Moto X via USB, the driver wouldn't 'install' properly. Status via Cntl Panel, Device & Printer, showed a device named XT1095 (yep that's my Moto X) but flagged with a yellow exclamation point and the declaration 'Driver Not Installed'.
After a NUMBER of uninstall/re-install episodes and delving into the Moto X (turn developer USB options ON/OFF), I tried the setup on my older Dell laptop. BINGO, everything worked like a hose! Hey, what's the difference?
Well, one thing is the Dell hardware is specifically limited to USB 2.0. My desktop PC running a quad core based motherboard has both USB 2.0 and 3.0 ports on it. Hum...
I did a clean install of the Moto Device Mgr and then connected my unlocked/running Moto X intentionally to a USB 2.0 port. KAZOOM, the device driver installed and all was working! Then, I unplugged the Android phone and re-installed it on a USB 3.0 port where it had previously failed to work. VAROOM, it came up and running nicely!
Methinks there's an issue here of technical due diligence in testing the Moto USB driver with various hardware manufacturer specific USB ports...
Update Driver Software
and click browse and point to the driver location. – samnaction Apr 17 '14 at 10:15