I have recently upgraded all computers to macOS Sierra V10.12.4 and found to my surprise that my MacBook Air's desktop files and folders are being mirrored on another, more public, computer on the network. To avoid embarrassment I want to stop this. I cannot find a way to do it - any help would be appreciated.
On the other computer that is public. Open iCloud preferences and turn of iCloud files. Consider signing out of iCloud entirely on that other computer.
For even more protection:
- Turn off iCloud document sync on the source computer (or move the sensitive files to another folder that doesn't sync to iCloud). This eliminates the ability to access those files from iOS, though.
- Store sensitive files in an encrypted DMG - they will still sync, but without a password to unlock the image - the files are not indexed or accessible.
In the future, Apple's new file system will allow file level encryption so that you can be less selective about sensitive files syncing but more selective about which are locked from inadvertent access (whether spotlight or just opening the file). This is probably 18 months off or more for total iOS / macOS adoption of APFS and file based encryption.