The reason for this failure is that the Big Sur installer application contains a single file Contents/SharedSupport/SharedSupport.dmg which is larger than 8GB. Pkgbuild: error: Cannot write package to 'InstallBigSur20B29.pkg'. Pkgbuild: Inferred install-location of /Applications Pkgbuild: Adding component at /Applications/Install macOS Big Sur.app/ With a Big Sur installer application this command will start working, but then fail: % pkgbuild -component '/Applications/Install macOS Big Sur.app/' InstallBigSur20B29.pkg This works for all InstallAssistants up to and including Catalina. You can use pkgbuild to build an installer package from an application, like this: pkgbuild -component '/Applications/Install macOS Catalina.app' InstallCatalina-10.15.7.pkg Unfortunately, even though “app in a dmg” has been a means of distributing software on macOS for nearly 20 years, most management systems cannot deal with this and expect an installer package (pkg). If you are using Munki (or one of the management systems that has integrated Munki, like SimpleMDM or Workspace One) you can wrap the application in a dmg. And since the “Install macOS Big Sur” application is huge (>12GB) it poses its own set of challenges.ĭifferent management systems have different means of deploying software.

Note: Apple calls the “Install macOS *” application “InstallAssistant.” I find this a useful shorthand and will use it.īefore you can use startosinstall, you need to somehow deploy the InstallAssitant on the client system. You can find this tool inside the “Install macOS Big Sur” application at: /Applications/Install macOS Big Sur.app/Contents/Resources/startosinstall When you want to provide automated workflows to upgrade to or erase-install macOS Big Sur, you can use the startosinstall tool.

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