All Document/ content moved to iCloud Drive folder

Question

My parents called me twice this year because of all their documents were gone.

After inspecting their iMac (osx 10.13), it appeared the whole content of Documents/ directory did move to iCloud Drive folder.

The first time, I switched the documents back to their initial folder and tough they might missclick something...

But it happened again two monthes later. They cannot made the same drag and drop error twice, so I wonder if there is some iCloud Drive black magic in the process.

Do someone have any idea?

Answer 1

It might be (so-called) "optimized storage" - there actually is a "Store in iCloud" button.

Choose "About This Mac" from the Apple () menu, then click Storage. (...) Click the Manage button to see recommendations for optimizing your storage (...) Click the Store in iCloud button (...) choose from these options:

(...)

Desktop and Documents. Store all files in these two locations in iCloud Drive. When storage space is needed, only the files you recently opened are kept on your Mac, so that you can easily work offline. Files that are stored only in the cloud show a download icon, which you can double-click to download the original file.

(from https://support.apple.com/en-us/HT206996)

You might want to have a look at that setting.