Something wrong with lastest versions Windows Sandbox and VMSMB-shared folders. (years ago all worked OK, now we have a problem).
On some file operations, looks like editing of memorymapped files, corruption occured and files are zeroed.
Shortest example to reproduce, using compilation and linking (corruption occured on linking phase).
Clone this project.
Run windows sandbox (check list for make Windows Sandbox works) with current folders shared as usual C:\Users\WDAGUtilityAccount\Desktop
01-start-windows-sandbox.bat
In sandbox, run cmd.exe as Administrator
Install "minimal" (actually some gigs) compiler suite to compile "Hello world"
cd Desktop
02-install-compilers-into-sanbox.bat
Then open another cmd.exe (we needed, because we should use new Path) as regular user, and
Build "Hello world"
cd Desktop
03-build-hello-world.bat
Resulting file completely zeroed!
04-why-exe-file-zeros.bat
If we copy Desktop somewhere outside mapped folders, and reproduce building all be OK.