https://www.askvg.com/fix-drives-appearing-twice-in-navigation-pane-of-windows-10-explorer-this-pc/
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” dialog box such as Save, Save as or Open in some 3rd party 32-bit programs. To remove the duplicate drive icon from there, you’ll need to perform the same steps in following key as well:
HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Explorer\Desktop\NameSpace\DelegateFolders
Under “DelegateFolders” key, delete {F5FB2C77-0E2F-4A16-A381-3E560C68BC83} key.
PS: If you want a ready-made Registry script to do the task automatically, its also given at the end of the above mentioned tutorial.