What keyboard is compatible with Mac mini pre-2012?

Hi Diblu- pretty much all of them will work with a Mac mini pre-2012.. either wired ( usb 2 or 3?) or Bluetooth… you could even use a Windows keyboard in a pinch ( eg for troubleshooting/emergency use) as long as it was a wired USB one… Bluetooth ones tend to be iffy for troubleshooting/emergency use, so it’s always good to have a wired usb keyboard around as a spare one

john B

Most any wired USB keyboard will work.

Even newer Apple Magic Keyboards will work.

Apple's newest Magic Keyboard with Touch ID may also work (unconfirmed), but the Touch ID function definitely will not.

There are a gazillion keyboards available and few that won't work.

I guarantee you that the "in-house tech" that said you need a pre-2012 keyboard is incorrect.

I just booted a 2005 model Mac mini with a new Apple Magic Keyboard and it works beautifully.

I agree with tbirdvet's suggestion that you have either a bad USB port(s) or a corrupted macOS installation or other major issue.

If a standard wired keyboard will not work then you have a major issue. Either in the port that you connect at or the OS is bad for some reason.