If you’re running Bootcamp on your Mac, or if you’re using a Hackintosh with Windows installed on its own drive, you’ll probably find that the Windows drive shows up in Mac OS as “Untitled”
While it obviously makes no difference to the operation of the computer, it can be aesthetically annoying, and there’s no way to rename the drive in OS X, as the rename option doesn’t even appear in the menu. Fortunately, the solution is very simple and only takes a minute.
To change the drive name, you first need to boot into Windows. Once you’re in Windows, in the search box, type “Disk Management” to open the Disk Management application.
Once in the Disk Management app, right click on your windows drive in the list, and click Properties.
In the window that pops up, type the name you want to give the drive in the box next to the drive icon. In my case, I just called the drive “Windows”. Then you can just click “Apply” and quit the Disk Management app.
The next time you boot into MacOS X, you’ll find that the Windows drive appears with its new label in place of “Untitled”.