In Mountain Lion, Apple introduced a new feature, iCloud.
iCloud is Apple’s “in cloud file storage” and it make it possible to store and sync files across your Macs and iOS devices.
Its similar to Dropbox, SkyDrive, SkyDrive and Google Drive.
By default, Apple proposes that all files are stored in iCloud and not locally on your Mac. Its not possible to change this in system preferences, but fortunately Apple have made it possible through a simple Terminal command.
(Mac Default iCloud storage)
Here is how you change it from for iCloud to Local storage:
Open a Terminal window and type (or paste) in the text below:
defaults write NSGlobalDomain NSDocumentSaveNewDocumentsToCloud -bool false
For changes to take effect, log out and log back in, or just reboot your Mac.
(Local storage)
If you want to return the system to store in iCloud as defalt, simply type (or paste) in the text below into the Terminal.
defaults write NSGlobalDomain NSDocumentSaveNewDocumentsToCloud -bool true
Again, log out and back in or reboot for changes to take effect.
TIPS: if you don’t want to restart your Mac, you can open Terminal and type in killall Finder. This will kill and restart the Finder.