Symantec has moved to block the sale of Microsoft's Windows Vista operating system accusing the software company of “deliberately and surreptitiously” misappropriating its technology for part of the operating system.

Symantec claims Microsoft has violated an agreement over how the new operating system, which is due to be launched later in the year after much delay, handles storage of large amounts of data on discs.

In a statement in response to Symantec’s complaint, Microsoft has said "Today’s filing stems from a very narrow disagreement over the terms of a 1996 contract with Veritas [which Symantec bought last year] to license volume management technology. We worked hard to try to resolve these issues with Symantec, but were not able to reach an agreement".

Microsoft first entered into a contract with Veritas in 1996 to license volume management technology. However it says "The contract ultimately gave Microsoft the option to buyout the rights to Veritas’ code and intellectual property rights".

In 2004, Microsoft exercised that right and purchased the IP rights.

However according to the Symantec, Microsoft has rewritten the volume management software for its next version of Windows in ways that were not allowed under the licence between the two companies.

Microsoft defended its adaptation of the technology: "These claims are unfounded because Microsoft actually purchased intellectual property rights for all relevant technologies from Veritas in 2004".

The move could delay the operating system even further.

We will keep you posted.