If you store a ton of files in these directories, you may not want to use this option, as it may push you to (or past) your iCloud storage allotment (which is capped at 5GB unless you pay a monthly fee). The iCloud Desktop and Documents window lets you know how much data you’ll be sending to Apple’s servers, but it doesn’t show the available storage in iCloud drive. MORE: macOS Sierra vs Windows 10: Why Apple Wins iCloud Desktop and Documents mirrors the files from those directories across all macOS Sierra computers, which allows you to keep the same desktop across all your MacBooks and any other Macs. The other perk is that it allows you to always access files from those directories on iOS devices, so those who always keep files on their Desktop and Documents directories can access them on the road with an iPhone or iPad. If you turned this setting on and wish to disable it, open System Preferences, Click iCloud, Click Options next to iCloud Drive and uncheck the box next to Desktop and Documents.
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