When you buy a second hand Mac you should do a clean install of OSX from a USB drive for security reasons. This sounds easy, but there are some problems you may run into. In this post we discuss 2 common, but cryptic, error messages and explain how to avoid them. Note that a clean installation requires you to have a USB drive with a bootable OSX installer. Note that on newer Macs you don’t need an USB drive as these support macOS Recovery over the Internet by pressing Option-Command-R after boot.
Error: This Item Is Temporarily Unavailable
This (most likely) means that the hard-disk was not empty during installation.
Resolution:
- Power on the machine and quickly press and hold the Alt/Option key until the boot menu appears
- Choose the USB drive (containing the OSX installer)
- Let the computer boot from the USB drive
- Choose an installation language
- Accept the Apple license agreement
- Choose “Utilities > Disk Utility” from the top menu (next to the apple logo)
- Erase the internal drive, by (GUID) re-partitioning with one partition (Mac OS Extended Journaled)
- Erase the single partition that the drive has (not needed if the previous step was done)
- Quit Disk Utility by closing the window
- Now selecting the drive to install to and proceed installation
See: https://www.youtube.com/watch?v=W7bPfNREVMU
Error: No packages were eligible for install
This means that the date should be set (back!) to a date when the certificate for the OS was valid.
Resolution:
- Power on the machine and quickly press and hold the Alt/Option key until the boot menu appears
- Choose the USB drive (containing the OSX installer)
- Let the computer boot from the USB drive
- Choose an installation language
- Accept the Apple license agreement
- Choose “Utilities > Terminal” from the top menu (next to the apple logo)
- A terminal window occurs with a prompt
- Type “date 0101010117” to set the date to “Jan 1st, 2017 1:01 AM”.
- Choose the last 2 digits “17” (means year “2017”) from the list below:
- 12 = Lion (10.7)
- 13 = Mountain Lion (10.8)
- 14 = Mavericks (10.9)
- 15 = Yosemite (10.10)
- 16 = El Capitan (10.11)
- 17 = Sierra (10.12)
- 18 = High Sierra (10.13)
- 19 = Mojave (10.14)
- 20 = Catalina (10.15)
- Type “exit” and reboot the machine to retry the installation