I just did a clean install of Mac OS X 10.10 (Yosemite) in my Macbook Air. Before installing 10.10, I erased the whole SSD and installed 10.10 from the web using Recovery Tools. And after the installation I signed in with my Apple ID. To my surprise, all the previous system settings from 10.9.4 are synced with 10.10 as well.

Is there a way to get back all the default system settings?

  • 10.10 is Yosimite. 10.9 is Mavericks – Vdub Nov 12 '14 at 20:26
  • Deleting preferences for one app is done via the command defaults delete <app-ID> (see this). – harrymc Nov 30 '14 at 10:15
  • 1
    So what do you mean when you say 'system settings'? – user187561 Dec 2 '14 at 4:19
  • I am not well familiar with Apple products, but something in mind that usually works with syncing settings in general, try to get into your Apple ID and modify sync settings, if there is an option to disable syncing current settings then modify it and check if the settings still exist, then perform a clean install again. Another approach is to try to see synced settings from your Yosemite OS after performing a clean installation, then disable it and after that key in your Apple ID. In the end I suggest that you call Apple care and check for a solution. – Ash Dec 2 '14 at 9:28
  • @David Koontz Can't he perform defaults delete * ? – Ash Dec 2 '14 at 9:30

Resetting the preferences of a single application is described in the article
How to reset an App’s Preferences :

Sometimes you may want to reset all settings of an app. This is often helpful when an app behaves strangely or crashes on start.

You can delete an apps settings using the command line. On OS X you access the command line using the Terminal app. Terminal is preinstalled on every Mac and can be found in /Applications/Utilities/ or using Spotlight:


In Terminal enter the following command:

defaults delete <application ID>

The application ID is in the form com.company.app. For example to delete the settings of Wokabulary enter:

defaults delete com.mrFridge.Wokabulary

to delete the Tincta settings enter:

defaults delete com.mrFridge.Tincta

Remember that this command will reset all your settings and you will need to re-adjust the applications settings.


Why don't you create a new profile and delete the current one ? It will give you standard system settings.


If you (or someone) have the time, I'm pretty sure it can be known by setting up a new user and starting to log every disk activity with sudo fs_usage -f filesys > ~/Documents/fs_usage_log.txt, just before logging in with the Apple ID. Then, take a look at the log to see what just happened, so you can get a clue, or maybe know what files to delete.

Of course, it's best to close as much applications as possible, so the log don't get too polluted.


I'm not sure what you mean by Yosemite defaults?

Presumably you mean like with a new user. If you mean settings saved in your Apple ID, you can sign out of iCloud in system preferences. It sounds like you want to start fresh. If so, just set up a new user in system preferences > Users/Groups and manually migrate whatever data from your original user. You'll need to select administrator access when prompted, and may need to reset permissions.

Best option I'd think is to use Migration Assistant with a new user. Here's an Apple link with explanation. This will set permissions for you (just use spotlight to find, or look in /Applications/Utilities.

This may not be relevant to you if you're using an Apple installed SSD. If you're using a DIY SSD, Trim support is tricky in Yosemite because of recent modifications to kext security management that affects Trim support. More here about Trim Enabler for Mac.

Good Luck!

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.