In the Windows 10 Technical Preview File Explorer defaults to the Home folder which shows Favorites, Frequent Folders and Recent Files.
To remove these folders we need to edit the registry. Click the Start button and then type regedit.exe and press Enter.
Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\HomeFolder. To make a backup of this folder right click it and then select Export and save it.
Expand the folders beneath HomeFolder and you will see the NameSpace and DelegateFolders. The latter contains three GUIDs for the Frequent Places Folder, Recent Items Instance Folder and the Favorites Folder respectively.
Right click on each GUID that you wish to remove and then select Delete and they will no longer appear in your Home Folder in File Explorer.