How to Reset Mac Settings to Default (Safely)

"Reset to default" means five different things depending on how much you want to lose. Start at the top of this list and stop as soon as the problem is gone. The last option erases everything, and almost nobody who searches this actually needs it.

Level 1: reset one app

Every app stores its settings in a preference file named after its bundle identifier. Delete it and the app starts fresh:

# find the file for an app
ls ~/Library/Preferences | grep -i appname

# quit the app first, then move the file aside rather than deleting
mv ~/Library/Preferences/com.example.app.plist ~/Desktop/

Two things to know. Quit the app first, because macOS caches preferences and will write the old ones back over your change. And move rather than delete, so you can put it back if the reset did not help. Sandboxed apps keep theirs inside ~/Library/Containers/<bundle id>/Data/Library/Preferences instead.

Level 2: reset the Dock or Finder

These two account for most "my Mac looks wrong" cases and both reset cleanly:

# Dock back to factory layout and behaviour
defaults delete com.apple.dock && killall Dock

# Finder back to defaults
defaults delete com.apple.finder && killall Finder

The Dock one restores the default set of icons, so note what you had pinned. Neither touches your files.

Level 3: undo hidden settings properly

If you have applied defaults write commands over the years, undo them with delete, not by writing the opposite value. macOS treats "set to false" and "never set" as different states for some settings:

# right
defaults delete com.apple.screencapture disable-shadow

# wrong: this adds a second change rather than removing yours
defaults write com.apple.screencapture disable-shadow -bool false

To see what a domain currently holds, so you know what to remove:

defaults read com.apple.dock
defaults domains | tr ',' '\n' | sort

Level 4: reset the peripherals and network

• Trackpad and mouse — defaults delete com.apple.AppleMultitouchTrackpad and log out.
• Network — move the files in /Library/Preferences/SystemConfiguration aside and restart, which rebuilds every network configuration.
• Bluetooth — move /Library/Preferences/com.apple.Bluetooth.plist aside and restart.
• NVRAM (Intel Macs) — hold Option-Command-P-R at startup. On Apple silicon this happens automatically and there is nothing to do.

Level 5: a new user account

Before erasing anything, create a fresh administrator account in System Settings → Users & Groups and log into it. It has every macOS default and none of your settings. If the problem disappears there, the cause is in your user account and you have just narrowed the search enormously. If it persists, the cause is system-wide or hardware.

What none of these levels touch

Worth knowing before you go further than you need to. Resetting preferences does not remove: your files, your apps, your keychain and saved passwords, your Wi-Fi networks (unless you reset the network configuration specifically), or anything in iCloud. It also does not fix hardware, and it does not remove a profile installed by an employer — managed settings are re-applied by the management system after any reset, which is why a work Mac keeps reverting to a policy you did not choose.

Level 6: Erase All Content and Settings

The nuclear option, and it is built in: System Settings → General → Transfer or Reset → Erase All Content and Settings. It wipes your data and settings and returns the Mac to a first-boot state, keeping the installed macOS version.

Back up first. Time Machine, or a copy of everything you care about on an external drive, verified before you start. This is the right step when selling a Mac or handing it on, and it is very rarely the right answer to a settings problem you could have solved at level 1.