- Restart your computer and the phone.
- Make sure that your computer is not behind a firewall or on a corporate network to complete next steps.
- Check that you have the latest updates installed on your computer. Use your computer’s Internet Explorer and go to www.update.microsoft.com.
- Disconnect your phone and other USB devices connected to your computer.
- If you have the lock screen password enabled, make sure your phone is unlocked before connecting it to the computer.
- Make sure that your phone has enough battery power and the phone is switched on. Connect a compatible USB cable first to the phone and then to the computer end.
- If your computer can detect your phone but cannot load the driver, check to see that your phone is listed under Portable devices in your computer’s Device Manager (press the Start button, type Device Manager and press enter).
- If Windows Device Manager indicates a device problem, that hardware will be marked with a yellow exclamation mark (!) to help you identify it. Try another USB port on your computer (do not use a USB hub or the ports located on the front of your computer).
- Try switching between USB connection modes to see which one is recognised better: On your phone swipe down from the top of the screen, tap the USB icon and switch connection mode between Mobile device (MTP) and USB memory
- You might also try connecting your phone to a different computer. This will validate whether the problem is with the USB connection on your computer.
Installing & updating Nokia X ADB drivers:
Finally if anything doesn’t work, you can download and Install ADB drivers. Read below to know how to update drivers, if your PC doesn’t detect your device. This method has been shared at XDA dev forums.
1. Download Latest ADB Drivers from here and extract it’s contents on to your desktop (or anywhere you like).
2. Connect your Nokia X/XL with USB Debugging On. (Settings–>USB Debugging).
3. Windows 8 users, you need to follow this guide to turn off signature verification. This is necessary as I cannot sign the drivers. Windows 7 users also have to do this by following this guide.
4. For Windows 7: Press Start and in search box, type “Device Manager” and open it.
For Windows 8: Use Search to find “Device Manager” and open it.
5. Now, under other device, right click the Nokia X with yellow triangle and choose “Update Driver”.
6. Browse to the Nokia X Updated USB Drivers folder in the zip package. And let it install.
7. After some time, it will install and Nokia X ADB Composite drivers will be installed.
8. Do it for the other Nokia X with yellow triangle as well.