“Your friends and family may not appreciate this truth, but that’s just the way it is sometimes,” Casey writes. “Luckily, MacBook owners can protect their sensitive files from prying eyes by password protecting specific folders.”
“Many paid programs offer similar functionality, but we prefer this free method built into [the Mac by] Apple that allows folders to be turned into protected disk images,” Casey writes. “We tested this on a MacBook Pro running macOS Sierra version 10.12.6 but research shows it works the same way going as far back as Mac OS X 10.6, Snow Leopard.”
Simple instructions for password protecting a folder on your Mac here.
MacDailyNews Note: When you’re finished using the documents on the secure disk image, be sure to eject the disk image. As long as it’s available on your desktop, anyone with access to your computer account can use the documents on it. To access the data in a disk image, just double-click it. When it appears on your desktop, and you can add, remove, and edit files on it just as you would with a disk. Lastly, for true security, don’t add the encrypted image’s password to your Mac’s Keychain!