Windows.
Viewing post in Isabella - Chasing Shadows Chapter 4.1 comments
No problems reported with the Windows version.
Download it again, or try this download
https://mega.nz/file/MCZjFRID#kpllUFC0wJMtDha0jjlaqkK4z6cxWadaLDrd9FGNARo
Download, unzip and run the exe, there's no "installing".