Windows 10 via Bootcamp: "Setup was unable to use the existing system partition..." I'm running macOS Sierra on an early 2015 MacBook Pro with a 500 GB SSD. 

I've been trying to get Windows 10 installed via Bootcamp by following this guide: https://support.apple.com/en-us/HT204990

I've allocated 80GB of space via the Bootcamp Assistant. 

I'm getting stuck at the following error:

"Setup was unable to use the existing system partition because it does not contain the required free space"

I can go larger, but am not confident that would resolve the issue (I've done some searching and others report an issue with 100GB) and I didn't really want to give Windows that much space.

Any ideas?
It turns out the error is misleading. I was able to resolve the issue and successfully complete installation by clearing space on the "EFI Partition" by following this guide: Unable to install Windows 8.1 using Bootcamp, system volume doesn&#39;t contain required free space?