Complex sentence: VMs distributed legally only have freely distributable operating system, as operating systems on VMs must be licensed; ready-to-use VMs with Microsoft Windows or Mac OS X, in particular, are not distributed, except for evaluation versions.
Split into simpler sentences: VMs distributed legally only have freely distributable operating system, as operating systems on VMs must be licensed. Ready-to-use VMs with Microsoft Windows or Mac OS X, in particular, are not distributed, except for evaluation versions.