I'm using developer preview of Yosemite for a while, now that Yosemite is released I want to have it installed on top of my Yosemite partition.

Clicking on "Download" in App Store Yosemite page, I see that I am prompted with an error note, saying :

Os X v10.10 is already installed on this computer. Use the Updates page to install the 10.10 update or if you would like to download the full OS X installer click Continue.

There's only two buttons; "Learn More" and "OK". OK does nothing, and there's no relevant update note regarding switching to full version of Yosemite so it's not rleevant neither.

How can I download full, final OS X Yosemite 10.10 release and install it on top of preview partition?

  • Sorry if it's a stupid question because it's not clear to me in the question but was there an update available in the app store for yosemite. Maybe you don't need to download the full installer but update to the latest version...?
    – doovers
    Oct 17, 2014 at 9:26
  • There is an update but it is about xcode and command line tools, and they're old so i dont think theyre related to full version.
    – Akaedintov
    Oct 17, 2014 at 13:12
  • I received Yosemite Beta 6 on October 15 -- the day before Yosemite was released. I am wondering if this brings us up to the gold master? It seems suspicious that a new beta version would be released when the master clearly had to be finished. I had the same experience as you did in the app store.
    – jalynn2
    Oct 17, 2014 at 17:39
  • @Akaedintov The installation and upgrade instructions vary depending on from where you received the beta version / GM candidate?
    – bmike
    Oct 17, 2014 at 18:22
  • I have Mac developer license, I downloaded the beta installer from developer.apple.com
    – Akaedintov
    Oct 17, 2014 at 18:33

2 Answers 2


All the coverage I've seen says to run what you have and 10.10.1 will convert all pre-release versions of OS X - including the latest GM candidates to the full production version.

You are free of course to go through the work to download the free version of the installer and see if it runs on your specific version of OS X but without knowing your exact build and source of the pre-release software, it's hard to be more specific.

  • The installer is downloaded from developer.apple.com, and my current build is Yosemite 10.10 (14A314h). May I ask where you read the article about 10.10.1 from ?
    – Akaedintov
    Oct 17, 2014 at 18:36
  • 1
    imore.com/… Oct 17, 2014 at 18:46
  • @bmike - what is the citation for "10.10.1 will convert all pre-release versions of OS X"? Oct 22, 2014 at 4:08

I came across the same error when trying to download the latest Yosemite Installer from the Mac App Store in order to do a clean install on top of my beta version of Yosemite.

OS X v10.10 is already installed on this computer. Use the Updates page to install the 10.10 update or if you would like to download the full OS X installer click Continue.

There was no 'Continue' button to click, just an 'OK' and 'Learn More' which did nothing.


The solution was to spoof my OS X version to a lower increment so that the App Store thinks you need the latest installer. To do this..

  1. Navigate to /System/Library/CoreServices and find the file named SystemVersion.plist
  2. Right click SystemVersion.plist and allow yourself 'Read/Write' permissions
  3. Open SystemVersion.plist with a code editor and change ProductVersion to 10.9
  4. Save the file, return to the App Store and click 'Download' on the Yosemite page

Following these steps allowed me to download the installer for my intended purpose! Hope it works for you. Instructions on unlocking a .plist file can be found here How do I unlock a .plist file so that I can change it?

  • Unfortunately this doesn't work anymore, app store crashes on open when doing this. Jun 8, 2015 at 13:30

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