With the release of macOS 10.12.4, it appears that Apple has made a change to the OS installer that blocks the installation of third-party packages which have been added to the OS installer. In my testing, I’ve verified the following tools are affected:
Note: There may be others, this list is what I’ve tested.
In each case, the OS install process proceeds without issues until the OS installer tries to install the third party installer package. At that point, the installation process fails and displays the message shown below:
The package "Package Name Goes Here" is not signed. Quit the installer to restart your computer and try again.
The error message displayed is misleading however, as this message may also appear if the package has been signed with a Developer ID Installer certificate.
In testing done by myself and others, we have found that there is one circumstance where you can still add a third-party installer package:
- If you are building a NetInstall NetBoot set using System Image Utility
- If the package is signed with a Developer ID Installer certificate.
Otherwise, the only installer packages I’ve seen which install correctly are packages which have been signed by Apple itself.
For more details, see below the jump.