Why Do My HEIC Photos Not Open on Windows?
HEIC is Apple's format and Windows needs an extension for it. Converting is usually simpler.
HEIC is the format iPhones use. It saves space, and Apple supports it everywhere. Windows does not, unless you install an extension from the Microsoft Store, and even then some programs still refuse.
So a Takeout export from an iPhone user lands on a Windows PC as thousands of files that will not open. The photos are fine; Windows just does not speak the format.
You can install the extension. Or you can convert to JPG, which every device and program on earth opens, and stop thinking about it.
The app converts HEIC to JPG and carries the metadata across, so the converted files keep their real capture date and location rather than arriving blank. It straightens sideways photos on the way. Conversion is a switch you turn on, so if you would rather keep HEIC, leave it off and only the dates are fixed. The first 500 photos are free.