Installing Wheezy on OSX

I try to install LinuxCNC via Virtualbox under OS X Mojave on my Macbook Pro.
I downloaded the linuxcnc-2.7.14-wheezy.iso, checked the SHA256 value. I downloaded it several times, last time someone did it for me via zsync, so it should be right.
When trying to mount, I get a "keine aktivierbaren Dateisysteme" - "no accessible file systems". I cannot open it and burning it via balenaEtcher results in a non readable USB stick.
Any idea?

Linuxcnc is a REALTIME OS so it will nor run under VirtualBOX invirerment
you realy need to get a STANDalone Main Real System if you want to drive a ,mashine

it can bi installed as a simulation only
see the wikipedia on this

LinuxCNC doesn't appear under www.realtimelinuxfoundation.org/
and I don't grasp what this has to do with being able to install or not.
It doesn't matter if I install it straight on the Mac, via Parallels or Virtual Machine - reaction time will differ, so what.
I need it for CAM: G-code production and simulation, not for running a CNC mill.
But I am happy to get any hint how to circumnavigate the expensive gap between CAD and the CNC mill. The least costly extension I found so far is MeshCAM, but still it is a bold investment for a few hobby related projects.

Fusion360 is free for hobby use it will do cad and cam

but still I wonder why someone made this huge effort to create a Mac version which cannot be mounted nor installed ...

Not sure if this helps you on a mac but I found the only reliable way to create a bootable USB was to use win32diskimager

I use DD on Linux and it always works.
It is normal that you can not read the USB with the Wheezy image on it, but it will boot and work.

I have installed the LinuxCNC Wheezy ISO and the LinuxCNC Stretch ISO as VirtualBox guests and VMware guests on my Macs without any problems.

Edit: I just downloaded the Wheezy ISO and created a new guest with the wheezy ISO image directly attached to the guests cdrom and it works flawlessly. This is with VirtualBox Version 6.0.12 r133076 on Mojave Version 10.14.6

I cannot choose it during startup, hence I cannot boot into Linux.

I'd have to first install a WIN version. Probably not the intention of the creator(s) of LinuxCNC