Windows 7 on External SSD - Black Screen When Booting

markthornton90 wrote:

My SSD has the W7 files on it. I did that using WinToUSB.

When I restart the MacBook and boot from the ‘EFI boot’, I then get the blank screen where I’m expecting the Windows setup.

Your SSD has no Apple drivers to support the Preboot Environment (WinPE). The drivers are for specific models of Apple Macs. A 2017 Mac has no Apple drivers for W7. See Install Windows 7 on your Mac using Boot Camp - Apple Support, which shows W7 64-bit being last supported on 2014 models.

Do you need Windows or very specifically W7? You can install W10 on your internal disk via Bootcamp, which will provide support for most software. If you want to run old software, use a VM. The other option is to find a 2014 Mac, running macOS Sierra or older and install W7 in BIOS mode (not EFI). W7 EFI is very buggy.

You posted in the Boot Camp Community but you are discussing a Virtual Machine.

Installation of Windows on an external drive is not supported by Boot Camp nor by Microsoft.

If you are having problems installing Windows using a virtual Machine you might try seeking assistance from the Virtual Machine developer or from Microsoft.

Either you can install W7 as a VM, and use the external disk for storing the vmdk, or you can use WinToUSB and try to install W7 in EFI Boot on the external SSD, as a non-VM installation.

You do not need WinToUSB for a virtual disk (vmdk) store on the external disk.

Please clarify the exact needs.