According to feedback from users in the community and on social media platforms, iCloud for Windows has some serious problems, including corrupted videos and displaying stranger photos.
Many users have reported that when using iPhone 13 Pro and iPhone 14 Pro models, videos recorded on iPhone cannot be played on iCloud for Windows after syncing, and a black screen with a flashing white line appears, making it impossible to watch normally.
Synchronized video shows white line black screen effect
What is even more worrisome is that MacRumors forum user sleeping_ghost explained that
"Videos recorded on iPhone 14 pro max do not display properly on iCloud for Windows, resulting in a black screen with scan lines. In a few cases, stills from unknown sources are inserted into the video after syncing, possibly from other people's iCloud accounts. I've seen family photos, soccer games, and other random photos of other people I've never seen in my life. Obviously, this is very worrisome, and now I no longer consider iCloud to be a very secure service."
It’s unclear whether the photos came from images of other iCloud users, but the likelihood is high. Users in the post gave feedback about seeing random families, children, soccer games and other similar photo content.
Deleting the iCloud for Windows app doesn’t seem to fix the problem, as it may be a server-side issue, and several people have reported the problem to Apple, who should have already started investigating the issue.