Security researchers are warning of almost a decade old issue with one of the Apple’s Mac feature which is potentially exposing the contents of files stored on password-protected encrypted drives. The “Quick Look” feature helps users preview photos, documents files, or a folder without opening them. However, these cached thumbnails are stored on the computer’s non-encrypted hard drive, at a known and unprotected location, even if those files/folders belong to an encrypted container, eventually revealing some of the content stored on encrypted drives.
Source: https://thehackernews.com/2018/06/apple-macos-quicklook.html