Talk:Mac OS X 10.6.8/@comment-69.120.130.130-20160221212317/@comment-24886041-20160223213254

Yes and no --  new hardware isn't directly compatible with 10.6, but your software is.

If you run VirtualBox or VMWare Fusion or Parallels Desktop, you can boot from an image of the backup disk inside that virtual environment, and it should start up just fine. This would mean that you'd be running 10.11 on your iMac, and, for example, VirtualBox on that, and inside VirtualBox you could either boot from the external HDD, or boot from an image (preferred) and run the software. Then you'd be running both environments at the same time. This also has the benefit that you can use snapshotting to save and restore state for the old setup.

You might get into trouble where the virtual hardware doesn't match the 2006 iMac hardware, in which case the backup might not boot.

You can also migrate the software directly to 10.11; for CS4, the electronic regulation no longer works, but there's a work around posted on Adobe's site; I'm not sure for Quark 8, as I haven't used Quark in years.