Our code is using .lowQualityThumbnail to generate a thumbnail, it stops working when users update to 15.2 . Test it with a regular jpg file for fileURL. The only way to make it work is to change it to .thumnail or remove it. It's not deprecated, is it a MacOS bug? customers don't want to keep updating the software. Everything works in MacOS 15.1 import QuickLookThumbnailing func generateThumbnail(for fileURL: URL, size: CGSize, scale: CGFloat) { let request = QLThumbnailGenerator.Request(fileAt: fileURL, size: size, scale: scale, representationTypes: .lowQualityThumbnail) QLThumbnailGenerator.shared.generateBestRepresentation(for: request) { thumbnail, error in if let error = error { print("Error generating thumbnail: \(error)") } else if let thumbnail = thumbnail { // Use the thumbnail let image = thumbnail.uiImage // Do something with the image } } }