3 Replies Latest reply: Dec 6, 2013 12:12 PM by Carolyn Samit
rozmoorhouse Level 1 (0 points)

Hi all, recently my iMac has begun to slow down significantly (this wasn't as a result of an update to Mavericks), so I have backed everything up and I am planning on 'starting over'. With the recovery tools of Mavericks, I have two main options: Firstly, I can 'reinstall' OS X, which, 'Use the built-in recovery disk to reinstall OS X while keeping your files and user settings intact'. Alternatively, I can, 'erase and reinstall' OS X, which just wipes the hard drive and installs a squeaky-clean new Mavericks. Since my Mac is a little clogged up with files, and I assume its depleting speed is a result of a handful of applications or the likes that I've installed, the, 'Erase and install' option seems like the best bet for me. Before I go ahead with this though, I was just wondering:


  • For what reason would you just reinstal lthe OS? Would this only be if your OS is playing up, or does it refresh certain other files as well?
  • What steps will I need to go through to set the OS/users up again? Do I need iCloud accounts or whatnot?
  • Is there anything else I need to know before I've gone ahead with the erase and reinstall?

OS X Mavericks (10.9)
  • Carolyn Samit Level 10 (103,365 points)

    Reinstalling OS X restores any missing or corrupted system files.


    If you reformat the disk, the Mac OS X will walk you through the intital setup including user accounts.


    Backup important data such as photos, video, documents, etc.




    Before you erase the disk...   not enough storage space can slow your Mac down. That may solve your problem before reformatting.


    Click your Apple menu  top left in your screen. From the drop down menu click About This Mac > More Info > Storage


    Make sure there's at least 15% free disk space.



    If installed, anti virus software can slow your Mac down as well.


    Good idea to check the startup disk on a timely basis.


    Launch Disk Utility located in HD > Applications > Utillities


    Select the startup disk on the left then select the First Aid tab.


    Click:  Verify Disk  (not Verify Disk Permissions)


    If DU reports errors, restart your Mac while holding down the Command + R keys. From there you should be able to acces the built in utilities in  OS X Recovery to repair the startup disk.


    Make sure to back up all important files first before using OS X Recovery.


    OS X Recover does require a broadband high speed internet connection.

  • rozmoorhouse Level 1 (0 points)

    Thanks Carolyn,


    I do indeed think that an anti- virus software is responsible for the issues. I am only using about 300gb. I have posted this as a seperate discussion on these forums- fixing file permissions did speed it up a lot, but I think it will just be easier to start over!

  • Carolyn Samit Level 10 (103,365 points)

    Which a/v software is installed ??   I may be just a matter of uninstalling that software.



    Gatekeeper prevents malware for you  ...


    Open System Preferences > Security & Privacy then select the General tab.


    Make sure either Mac App Store or Mac App Store and identified developers is selected. If that area is grayed out, click the padlock icon to proceed.


    OS X: About Gatekeeper