Minimum disk partition for Windows installation increased to 48 GB? I am currently on Mac OS Mojave 10.14.6. Boot camp assistant is not allowing me to reduce the Windows 10 partition size to a value lower than 48 GB. I only have a 256 GB SSD and 48 GB seems to be a lot. I read online and watched a few videos on Boot Camp and most of them stated that Boot Camp requires a minimum of 30 GB. (They are probably outdated?)

Microsoft's minimum system requirements indicate min disk space as 32 GB. Is there any way to override Boot Camp assistant to allow for a lower size partition? Is 48 GB the new minimum space requirement?

My only intention of using Windows is for playing games off my external hard disk. 

I am also considering to install Windows 7 or 8.1 to save some space while maintaining compatibility with games. Thus, allocating 48 GB is not optimal.
Boot camp assistant is not allowing me to reduce the Windows 10 partition size to a value lower than 48 GB.


That sounds about right as a practical lower limit for Windows 10. The Microsoft system requirements you're referring to are the absolute minimum resources required for the operating system to be installed; using Windows with that little disk space will be painful, and you are likely to have difficulty installing and using even basic desktop applications, let alone games.

(Running games from an external hard drive is inadvisable. Not all games will even run from an external drive, and performance will suffer heavily.)


  I am also considering to install Windows 7 or 8.1 to save some space while maintaining compatibility with games.


Don't. Both of those operating systems have exited their mainstream support phases, and the extended support phase for Windows 7 is ending in January 2020. Using them for a new system is a bad idea.