Windows 10 Version 1703 is obsolete and the media creation tool has been updated to only download the latest version of Windows 10. This guide is thus obsolete. My guide Windows 10 will instruct in downloading the latest version of Windows 10 which is recommended in most cases as well as the available workarounds to download a ISO of earlier versions.
Windows 10 RS2 (Version 1703) Installation .isos can be Downloaded from Microsoft by visiting their website. Open up Google Chrome:
Search for Windows 10 Media Creation Tool: 
This will take you to the software download page for the Windows 10 Media Creation Tool if you are using a computer that is running Windows 7 or later.
The Media Creation Tool is a small application which can be used to Download Windows 10 Setup Files and Create a Windows 10 .iso. The .isos created from the Windows 10 Media Creation are multi-edition and the Media Creation Tool checks the setup files before creating the installation .iso reducing installation failure via the selection of the wrong Windows Edition or from obtaining an incomplete download.
Select Download Tool now:
Wait for the tool to Download:
Then open your Download folder:
Right click the MediaCreationTool.exe and select properties: 
Select the Details tab: 
Check the file version in this case the version is 10.0.15063.0 which means the Media Creation Tool is for Build 15063 otherwise known as RS2, version 1703 or the Creators Update:
Double click the MediaCreationTool to launch it:
Accept the User Account Prompt:
The Windows splash screen will show:
Then the setup will get ready:
Accept the license agreement:
The setup will get ready again:
Select Create Installation Media for another PC:
I will download an English UK (English International) installation .iso:
The Windows 10 Media Creation Tool will automatically select the Language, Edition and architecture matching your current install. These are normally correct.
Note if you are running Windows 7 English even with UK customisations, Microsoft will assume that the install is English (US).
To switch to English (UK) ensure you uncheck Use "Recommended Settings for this PC" and select English (UK) opposed to English (US):
The tool gives the options of three "Editions" however each Edition here is actually multi-Edition itself and the Windows 10 Edition .iso and the Windows 10 Home Single Language created by the Media Creation Tool are identical.
- The Windows 10 Edition .iso includes; Windows 10 Home, Windows 10 Pro, Windows 10 Home Single Language and Windows 10 Education.
- The Windows 10 Home Single Language Edition .iso includes; Windows 10 Home, Windows 10 Pro, Windows 10 Home Single Language and Windows 10 Education.
- The rarely used European Commission Windows 10 N Edition .iso includes; Windows 10 Home N, Windows 10 Pro N and Windows 10 Education N.
I advise using the 64 Bit (x64) architecture in almost all cases as the 32 Bit (x86) architecture is more or less falling into obsolesce,
Select .iso file. The tool can make a Bootable USB directly but in my experience this is less reliable than downloading the .iso and creating a Bootable USB with Rufus.
Select next:
You'll be prompted for a save location:
The Windows 10 Media Creation Tool will now Download the Windows 10 setup files:
It will then spend some time checking the files its downloaded to make sure they are intact:
Then it will create a Bootable USB: 
It will tell you to Burn the .iso to a DVD, ignore this completely and select Finish. Optical Drives are obsolete and a multitude of installation problems occur on systems that do have Optical Drives due to badly burned DVDs or via the Optical Drive being blocked via Secure Boot.
The Windows 10 Media Creation Tool setup will now clear up any temporary files and close: 
Now that you have the installation .iso you can mount it via Windows Explorer (Windows 8 or Later) and launch the setup to perform an in place upgrade or you can use Rufus to Create a Bootable USB.
For more details see Creating a Windows 10 RS2 Bootable USB for a UEFI BIOS.
