How to create a VM to run a previous version of OSX

Hello,

I am currently trying to run a program called 3d Equalizer and it won't run on Sierra. I emailed the developers and they mentioned that Apple changed some infrastructure in OSX 10.12 (Sierra). As a consequence many X11 apps (including 3DE) are not working anymore. They mentioned a way around this was to downgrade the OSX.

I am wondering if creating and running El Capitan (the previous version) on VM would solve this issue? If so, what would be the optimal way to create the VM on my current OSX so I can run 3d equalizer on it. I prefer this to downgrading my whole OSX which could result in some loss to current files.

Thanks!

Some folks have solved problems similiar to yours by partitioning their hard drive and running a previous version of OS X on one partition and the latest on the other. You can do some research on that and probably come up with a fairly good procedure for the process.