If you have any updates pending make sure to update Visual Studio straight away. This was the final fix for me, but there’s probably one more thing that you have to do. Click on “modify” (which may be hidden under “more”). In the window that pops up select “Desktop development with C++” and begin the installation using the button in the lower right corner.
My issue was a problem with UE4 communicating w Visual Studio after upgrading to Windows 10. Just to add to this solution: Be sure under Editor Preferences/General/Source Code/Accessor, that your version of Visual Studio is selected in the drop down menu.