Starting from an unknown version of Windows 10, programs can no longer access dehydrated (online-only, placeholder) files with CreateFile(Ex) normally.
Consider the following excerpt:
// By default (if the program does not have a manifest, so it runs in Windows Vista mode),
// RtlQueryProcessPlaceholderCompatibilityMode returns PHCM_DISGUISE_PLACEHOLDER, and
// RtlQueryThreadPlaceholderCompatibilityMode returns PHCM_APPLICATION_DEFAULT.