What is safe to delete in order for system to work properly?

Solution 1:

Most of the applications you'll delete are going to be restored the next time there is a software update, and even still it'll only save superficial amount of space. For example, the Mission Control, Launchpad, Dashboard, Time Machine, etc. apps are all less than half a meg, and only serve as links to call upon these features via Dock or Finder.

If you want to make a substantial cut on space without making your mac bulimic, i suggest Monolingual, which deletes unused language support (which is usually around 500 MB to 2 GB) and redundant app binaries.

Most Mac apps are "universal," meaning they support both Intel and (the older) PowerPC processor architectures, by having every application contain a binary compiled for each. If you're running an Intel Mac, monolingual can be used to delete the unused app binaries, saving 1-2 GB

Solution 2:

Is also depends whether your system is used as workstation or server.

For our server usage we do delete this:

$ sudo rm -R /Applications/Automator.app /Applications/Chess.app /Applications/Mission\ Control.app /Applications/Stickies.app /Applications/Utilities/AppleScript\ Editor.app /Applications/Utilities/Audio\ MIDI\ Setup.app /Applications/Utilities/Bluetooth\ File\ Exchange.app /Applications/Utilities/DigitalColor\ Meter.app /Applications/Utilities/Grab.app /Applications/Utilities/Grapher.app /Applications/Utilities/Podcast\ Capture.app /Applications/Utilities/Podcast\ Publisher.app /Applications/Utilities/RAID\ Utility.app /Applications/Utilities/VoiceOver\ Utility.app /Applications/Utilities/Xsan\ Admin.app /Applications/Utilities/Boot\ Camp\ Assistant.app /Applications/Image\ Capture.app

$ sudo rm -R "/Library/Application Support/Apple/Mail" "/Library/Application Support/Apple/Grapher" "/Library/Application Support/Apple/iChat Icons" "/Library/Application Support/Apple/Automator/Workflows" "/Library/Application Support/iLifeMediaBrowser" "/Library/Application Support/ProApps/Internal Plug-Ins/BrowserKit/iLife.bkplugin" "/Library/Application Support/Script Editor/Templates" "/Library/Printers/Canon" "/Library/Printers/EPSON" "/Library/Image Capture" "/Library/Documentation/Help" "/Library/Scripts/iChat" "/Library/Scripts/ColorSync" "/Library/Scripts/Mail Scripts" "/Library/Scripts/Printing Scripts" "/Library/Scripts/UI Element Scripts" "/Library/Scripts/VoiceOver" "/Library/Audio" "/Library/Internet Plug-Ins" "/Library/Modem Scripts" "/Library/iChat" "/Library/QuickTime" "/Library/iTunes" "/Library/LaunchDaemons/com.apple.remotepairtool.plist" "/Library/PodcastProducer" "/System/Library/PodcastProducer" "/System/Library/Compositions" "/System/Library/LinguisticData" "/System/Library/Speech" "/System/Library/Spelling" "/System/Library/InternetAccounts" "/System/Library/Automator" "/System/Library/QuickTime" "/System/Library/InternetAccounts" "/System/Library/Image Capture" "/System/Library/ScreenReader" "/System/Library/Address Book Plug-Ins" "/System/Library/Services/AppleSpell.service"

$ sudo rm -R /System/Library/UserEventPlugins/CaptiveUserAgent.plugin /System/Library/UserEventPlugins/CaptiveSystemAgent.plugin /System/Library/UserEventPlugins/AirPortUserAgent.plugin /System/Library/UserEventPlugins/iCalAlarmAgent.plugin

$ sudo rm "/Library/Desktop Pictures/*.jpg" "/Library/Widgets/*.wdgt"

$ sudo rm -R /System/Library/PreferencePanes/FibreChannel.prefPane /System/Library/PreferencePanes/InternetAccounts.prefPane /System/Library/PreferencePanes/Speech.prefPane /System/Library/PreferencePanes/Ink.prefPane /System/Library/PreferencePanes/Trackpad.prefPane /System/Library/PreferencePanes/Mac.prefPane /System/Library/PreferencePanes/Xsan.prefPane /System/Library/PreferencePanes/MobileMe.prefPane /System/Library/PreferencePanes/iCloudPref.prefPane "/System/Library/PreferencePanes/ParentalControls.prefPane"