Hi Giony,
Let’s try these methods and check if it helps.
Method 1: Uninstall and then reconnect the external hard drive
This method resolves issues where the currently loaded USB driver has become unstable or corrupt.
a. Press Windows Key + X, click on
Device Manager.
b. Click Disk Drives from the list of hardware.
c. Right-click the USB external hard drive with the issue, and click
Uninstall.
d. After the hard drive is uninstalled, unplug the USB cable.
e. Wait for 1 minute and then reconnect the USB cable. The driver should automatically load (You may also try installing latest drivers from the manufacturer’s website).
f. Check for the USB drive in Windows Explorer.
Method 2: Set up a drive for File History
http://windows.microsoft.com/en-IN/windows-8/set-drive-file-history
For more information, refer to the link.
**How to use File History** ****
Do let us know about the results. We will be happy to assist you.