Mac Mini won't open Startup Manager

I have recently obtained a Mac Mini second-hand from an organisation. When I power on the device it boots Windows 7, however, I'm unable to boot from a USB due to the Mac Mini not opening it's Startup Manager/BIOS/Boot Menu/Open Firmware... whatever it's called.

I've tried Alt, F8-12 and even tried Shift for safe mode but every time it boots Windows 7.

If the organisation has blocked the boot menu from loading is there a way to unblock it (and possibly boot from a USB).

Edit: I only own a Windows QWERTY keyboard... is that the issue?

Cheers.

Solution 1:

It’s possible that your Windows-specific keyboard isn’t sending the correct keycode for the Option (Alt) key. To rule out hardware damage, have you confirmed that the Alt key works when booted into Windows or plugged into a different computer?

A workaround is to open the Mac Mini, disconnect the hard drive, and attach a USB flash drive containing a macOS installer (How to create a bootable installer for macOS). You’d still need a way to install onto the hard drive, which means buying an external USB enclosure for the internal drive... I think it’s just easier to try an Apple keyboard.