A recent report issued by security vendor Symantec claims that Microsoft's forthcoming OS (operating system), Vista, could be less stable than Windows XP.

With the OS still in beta – and not due to come to market until January 2007 at the earliest – Symantec’s researchers examined the part of the software that handled networking in build 5270 of the software. They concluded that since large parts of Vista had been rewritten from scratch, it had introduced an entirely new set of problems.

"Microsoft has removed a large body of tried and tested code and replaced it with freshly written code, complete with new corner cases and defects," CNet News reported the company as saying in Windows Vista Network Attack Surface Analysis: A Broad Overview.

Although these problems have subsequently been fixed in the more recent build 5384, the fact that Vista exhibited a new class of security and stability issues was probably indicative of what lay ahead for the months after it first ships. The current developer build of Vista is 5472.

"Vista is one of the most important technologies that will be released over the next year, and people should understand the ramifications of a virgin network stack," Oliver Friedrichs of Symantec said.

But Microsoft had a robust response. "Given that Windows Vista is still in the beta stage of the development and not yet final, the claims made in this report are, at best, premature," it said.

Symantec's story will look to some like a self-interested swipe, now that the two companies are direct competitors in the market for add-on security software. As valid as the criticisms might be, the fact that a brand-new OS exhibits a previously unknown set of security issues is hardly surprising.

More important will be the number of security updates Microsoft finds itself having to issue in the first months of its existence, and the ability of business users to adapt to some of its new – and potentially problematic – features, such as IPv6 support.