1. Press WIN+R keys together to open RUN dialog box. You can also open it from WIN+X menu. Now type regedit in RUN dialog box and press Enter. It'll open Registry Editor.
2. Now go to following key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Desktop\NameSpace\DelegateFolders
3. Under "DelegateFolders" key, you'll find {F5FB2C77-0E2F-4A16-A381-3E560C68BC83} key.
4. Now delete the {F5FB2C77-0E2F-4A16-A381-3E560C68BC83} key and it'll immediately remove the duplicate drive icons from This PC's Navigation Pane.
Now you'll no longer see any drive icon twice in the Navigation Pane of This PC.
NOTE: If you are using 64-bit edition of Windows 10, you may notice that the drive icon is still present in "Browse"...