Microsoft has abandoned a plan to ease the virtualisation restrictions of its Windows Vista operating system. 

The company currently allows users of Vista Ultimate and Vista Business to run the software in a virtual compartment, for instance on VMware, Parallels or Microsoft's Virtual PC.

Consumers who purchase Vista Home Basic ($199) or Vista Home Premium ($249) do not have this option.

Microsoft had originally planned to expand the virtualisation offering on 20 June. The company did not explain the reason for its change of mind, other than claiming that it was based on a "reassessment" of policies.

The licensing terms were intended to discourage less tech-savvy users from running the software in a virtual system.

Microsoft argues that virtualisation presents the user with security risks and is trying to limit the technology to educated users and businesses.

But Microsoft also forced Mac users to purchase Vista Ultimate at $399 or Vista Business at $299 if they wanted to run Windows virtually.

Such a strategy is especially useful for users who require access to a single application that is available exclusively on Windows, or to users who are switching operating systems.