What’s the best way to physically secure iMacs in a public 24/7 exhibition?

For a permanent installation, physically bolting the iMac base to the desk is much stronger than relying on a cable alone. Use substantial bolts with large washers on both sides of the desk and locking nuts so the fasteners can’t pull through the aluminum base or tabletop. If you need something less destructive, a thick board or bracket screwed over the foot can hold it down, as long as the design prevents someone from sliding the iMac out. A heavy chain routed through a suitable cable-management opening is another option.

Since these will be accessible to the public around the clock, I’d build or buy a proper locking kiosk rather than depend on one cable looped around the stand. A steel frame can surround the iMac, provide a dedicated anchor point, and clamp the base to a mounting plate. Depending on the design, you could also use a permanently mounted industrial keyboard and trackpad, or consider a Mac mini in a locked enclosure connected to a separate display.

In places like hospitals, these systems are commonly installed inside custom ventilated locking cages. That’s the most robust approach for unattended public equipment. Disabling the USB ports or using a basic padlock won’t solve the main problem, since those measures can often be bypassed or defeated if someone has enough time.