This used to be so easy; download an installer, save it to an external drive, use it on as many Macs as you'd like. Not anymore... I’m trying to update my wife’s MBP. This is an employer provided ...

If you have a spare hard drive lying around, you could use the existing recovery partition to install the OS on to that, even if just temporarily. If you have a friend with a Mac, he could download ...

macOS Monterey version 12 is a stable, lightweight upgrade that works great on older Macs, and you can use the direct DMG or ISO links to download, install, upgrade, or downgrade your system easily.

If you receive an error message indicating that your Mac's firmware is out-of-date, and hence cannot accept installation of Mac OS X from a CD/DVD -- specifically ...