Parallels played catch-up with VMware with the release of Parallels Desktop 7 Build 7.0.15050, an update to the virtualization software for Mac OS X. The free update adds support for Windows 8 Developer Preview and enables installation of Lion as a guest OS without using the App Store. VMware Fusion 4 already has both of these features. The Parallels update also adds support for Ubuntu 11.10 Linux and includes several stability and performance enhancements. The Build 7.0.15050 update is available from within Parallels Desktop 7 in the Parallels Desktop menu.

Parallels Desktop 7 was the first version to support Lion in a virtual machine. However, the only way to install it was to download the 3.5 GB Lion installer from Apple -- even if you already had downloaded and saved the Lion installer file, "Install Lion.app". The Build 7.0.15050 fixes this, enabling a user to create a virtual machine containing Lion with an already downloaded installer.

In addition to supporting Windows 8 Developer Preview as a guest OS, the new build updated the Parallels Wizard so that you can download and install Windows 8 with a single click.

Build 7.0.15050 also adds an option in full-screen mode that enables users to retain the resolution used in windows mode. It fixes a problem when disconnecting the Apple USB Ethernet Adapter and improves support for non-English keyboard layouts. There is also improved migration of recent Linux versions from a PC to a virtual machine on the Mac.

If you've tried Parallels Desktop 7 Build 7.0.15050 .