Today I read:

Apple today released an updated golden master (GM) version of macOS Sierra to developers… The new GM seed is build 16A323, while the build released last week was 16A320.

After downloading, in the Finder > Get Info of ‘Install macOS Sierra.app’ I see ‘Version: 12.0.49’ but no build number.

How to identifier the build number of a macOS installer?

My goal is to verify what installer I may be using.

6 Answers 6


The most reliable way of telling the build number is to check the SystemVersion.plist file inside the installer's OS image file (and not the build number of the installer app itself).

  1. Mount /Applications/Install macOS Sierra.app/Contents/SharedSupport/InstallESD.dmg
  2. Mount /Volumes/OS X Install ESD/BaseSystem.dmg (hidden file)
  3. Open /Volumes/OS X Base System/System/Library/CoreServices/SystemVersion.plist and examine the build number under <key>ProductBuildVersion</key>
  • yep, that's the only way. Commented Sep 21, 2016 at 13:10
  • There is no BaseSystem.dmg file there? Even though it's hidden, termal ls should be able to see it, right? imgur.com/6G7JfY9
    – yspreen
    Commented Apr 3, 2018 at 6:24

To determine the macOS Sierra GM build number use:

cat "/Applications/Install macOS Sierra.app/Contents/Info.plist" | grep -A 1 DTSDKBuild

Please apply the leading portion of the path if your Install macOS Sierra.app resides elsewhere.

  • I've seen that value be off from the installed build though...
    – MacManager
    Commented Sep 16, 2016 at 1:24
  • On High Sierra.app it worked, on El Capitan.app the info.plist was empty xD
    – Shayan
    Commented Oct 22, 2019 at 17:26
  • 1
    @Shayan Modify the path to the respective installer app (e.g. Install macOS Catalina.app, Install macOS Mojave.app or Install OS X El Capitan.app instead of Install macOS Sierra.app) - the build number of the macOS installer mustn't be confused with the build number of the installed base system by this installer (which usually is +2: e.g. 16A320 > 16A322). Chris.P provided the proper answer to check the build number of the installed base system (which is a temporary one!). The final build number can be found in the InstallESD.dmg.
    – klanomath
    Commented Oct 22, 2019 at 17:46

Hmm... I know when you're booted from the same major version of the OS (10.12, in this case) you can open System Image Utility and select the Install Assistant from the Sources menu and it'll tell you the build number.

But, it will only show the installer (or other volumes) that it can image, which have to match the major version of the booted system. So if you're in 10.11 now and want to see the build number of a 10.12 installer that won't work.


To determine the macOS High Sierra build number use:

  1. Mount /Applications/Install\ macOS\ High\ Sierra.app/Contents/SharedSupport/BaseSystem.dmg
  2. Open /Volumes/OS X Base System/System/Library/CoreServices/SystemVersion.plist
  3. Find the version number under <key>ProductBuildVersion</key>
  • 1
    How does this differ from the accepted Answer? Commented Sep 26, 2017 at 14:24
  • It works on High Sierra. BaseSystem.dmg location changed
    – yspreen
    Commented Apr 3, 2018 at 6:26


Since macOS Mojave, a lot of things have changed. I hope this newer answer remains valid for at least a couple of releases. I'm listing down few different methods, just in case one becomes obsolete.

Below commands assume you have already cd to /Applications/Install macOS XXX.app/Contents

  1. cat Info.plist| grep -A 1 DTPlatformVersion should give you the full version like <string>10.15.6</string>

  2. cat Info.plist | grep -A 1 CFBundleShortVersionString should give you should give you the minor version (postfix after 10.x) like <string>15.6.00</string>

  3. cat version.plist| grep -A 1 CFBundleShortVersionString should give you should give you the minor version (postfix after 10.x) like <string>15.6.00</string>

  4. cat SharedSupport/InstallInfo.plist | grep -E '[0-9]{1,3}\.[0-9]{1,2}\.[0-9]{1,2}' should most probably be able to give you the version in format XX.XX.XX

  • 3
    There is no need to cat, grep pattern file works better. Also defaults read /Applications/Install macOS *.app/Contents/Info.plist CFBundleShortVersionString will give you the expected result without the XML stuff.
    – nohillside
    Commented Jul 17, 2020 at 11:03
  • There is no need to use Terminal as these files are readable in the preview pane in Finder. Commented Jul 18, 2020 at 5:09
  • @user3439894 I agree, however, it's much easier to provide and follow instructions that are simple to copy-paste in a terminal than laborious step-by-step guides for GUI which are error-prone. Commented Jul 18, 2020 at 10:10

To find the build number once macOS Sierra is installed:

  1. Choose Apple Menu > About This Mac
  2. Choose System Report... to start System Information app
  3. Choose Software from left side
  4. From right side find "System Version: macOS 10.12 (build number here)"
  • 1
    This Question is about the macOS install-er rather than the install-ed macOS. Commented Mar 11, 2017 at 22:49

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .