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RSSTutorial: Change Mac OS X System Version
Feb 10
Tutorial, Uncategorized OSX 6 Comments
As I’ve said, nearly the exact same process is used for this as for changing the iPhone OS version, since OSX and iPhone OS are based on the same core, but I’m writing this with more desktop OSX-specific steps and screenshots.
I suppose the question would arise, “Why would one want to do this?” On Leopard, it is incredibly useful in situations where one may wish to install software that claims to require an update that you don’t want to install. I’ll be demonstrating on Snow Leopard, but the procedure is the same on both. In my demonstration, I will be changing the version number from 10.6.2 to 10.7.0. This has no practical use, but will suffice for demonstration purposes.
Before:
Requirements:
1. Mac OS X
2. A basic knowledge of Terminal
Steps:
1. Open Terminal.
2. Type sudo nano -w /System/Library/CoreServices/SystemVersion.plist
Does the file path look familiar from my last tutorial? 
3. Press Enter. You will be prompted for your password. Type it in. You won’t see it on your screen. Press Enter again.
4. Use the arrow keys to navigate to the end of the 10.6.2 under ProductUserVisibleVersion and erase the version number. Enter in a version number of your choice.
5. Repeat for the version number displayed under ProductVersion.
6. Press 
X (Control-X) to exit. It will ask you if you wish to “save modified buffer.” Press y. It will then ask for a file name to write. Press Enter to accept the default.
7. Exit Terminal.
After:
Needless to say, to reverse this process, just follow the steps again, changing the version number back to the original system version.
Dec 28, 2010 @ 07:16:24
Thank you so much. it worked quite well and you save me a lot of time!
Nov 06, 2011 @ 09:44:22
hi
i changed it on the file and now my mac won’t start. i try to do this on terminal but i’m not as user, because I’m using terminal located in startup. can you help me?
Jan 09, 2012 @ 17:17:27
I used this method and after a reboot all my system apps(Safari, software update, app store, dashboard, spotlight etc.) were broken and now they won’t start. Reverting the changes doesn’t work either. It says that I have to check with a developer if the application is compatible with the current version of the operating system.
The worst part is that even the Installer application is broken, so I can’t install packages or reinstall programs.
What to do? Please contact me..
Jan 15, 2012 @ 20:47:13
Why would you change MAJOR system releases?
It will try to install lion updates, and your system will be hosed.
DO NOT DO THIS. You can change minor system levels like 10.6.7 to 10.6.8 but not 10.6.7 to 10.7, don’t ever do this.
I don’t know why you’d want to change major releases.
Jan 19, 2012 @ 14:40:12
Heh, yes I did the very same thing, in order to get the iBooks Author program to work under Snow Leopard. Trouble is, I ran Software Update after and it wanted to download a new version of Safari & iTunes, which I didn’t give a second thought. Upon restart, the same issue arises with most apps: they won’t launch. System Preferences, 3rd Party apps and TextEdit remain unaffected, though. I reversed the edits to the .plist file and rebooted, but the same issues persist. I’m enabling root user, now, I’ll see if I can’t launch the apps from there.
Jan 19, 2012 @ 16:17:53
Just in case anybody else runs into this issue, repairing the Disk Permissions with Disk Utility (found in your Applications/Utilities folder) will solve the problem of applications not launching (including the Installer).
However, it won’t solve the problem of needing to downgrade your version of, say, Safari, if you happened to update it using your falsified OS X version number. In order to do that, it seems a full reinstall of a Combo Update package for whatever OS you were using (Leopard, Snow Leopard) is required.