cmake -G Ninja has errors

cmake 4.2.1
Win11 home (x86-64)
Ninja 1.13.1 (windows version)
cygwin 3.7.0

I am brand new to cmake. A complete novice. So, if my question is dumb then that tells the truth about me.

cmake -G Ninja -B build produces the following error:
'/usr/bin/ninja.exe' '-C' '/d/home/skidmarks/Projects/Test/cmake/src/build/CMakeFiles/CMakeScratch/TryCompile-hiEt3u' '-t' 'recompact'

failed with:

ninja: fatal: chdir to '/d/home/skidmarks/Projects/Test/cmake/src/build/CMakeFiles/CMakeScratch/TryCompile-hiEt3u' - No such file or directory

The file/direcotry ‘’‘d/home/skidmarks/Projects/Test/cmake/src/build/CMakeFiles/CMakeScratch/TryCompile-hiEt3u’" does not exist. Who creates this file? The user? cmake? And if it’s the user where do I find out what should be in it.