The mad rush to commercial implementations of Windows Vista does not seem to have happened despite Microsoft's mild protestations to the contrary.

The operating system has reached the dizzy heights of a little over seven per cent of all desktop OS installations, according to Net Applications, and possibly fewer than one per cent in the commercial area, according to Sunbelt Software.

There are several possible reasons put forward for this: hardware being too old to cope with Vista's requirements, everyone waiting for Service Pack 1, the cost of re-training staff on the new platform and the lack of interest in some of its whizzier aspects.

However, the real killer for many organisations is the lack of certified applications for the platform, and the incapacity to get many existing applications to work under Vista.

We are not just talking about personal productivity apps that make one or two people's lives easier.

A year down the track, and things like the very widely used iPass client for mobile users (enabling users to aggregate Wi-Fi, broadband and modem charges for mobile connectivity) is still not Vista compliant.

For those who depend on connectivity while on the road, this means that Vista on laptops is a no-no unless they want to pay full commercial rates for every connection made away from the office and home.

It is not just iPass, however, and the list of incompatible applications seems longer than the list of compatible ones.

Only around 500 applications are shown on Microsoft's own site as being 'Compatible with Microsoft Vista' and around 1,500 as 'Working with Microsoft Vista'.

OK, such certification is not free. It comes in at around $1,000 per application (not paid to Microsoft, but to independent testing groups) which may put off the smaller independent software vendor (ISV), but should not be a big problem for those taking Vista seriously.

Even with Microsoft making available packages such as the Application Compatibility Toolkit, which aims to show where problems may lie, there seems an awful amount of slothfulness out there in ISV land.

Where compatibility is possible, finding the right version can be a problem. Many vendors still have dual applications, one that is Vista compatible and one that is not.

For the corporate user, this can mean two different applications that can have different problems. For the vendor, it means two different possible types of call coming into the help desk.

Indeed, one of Microsoft's own Vista launch partners in the UK, Newham Borough Council, pulled its planned 1,500 seat Vista implementation once it saw how many applications would be incapable of running under Vista, or would not be fully supported by the vendors involved.

Why are so many applications not compatible with Vista? It is easy to blame Microsoft, but it is not the main villain of the piece.

The company has made tools and guidance available from a very early stage, even if some involved cost to the ISV. Although it is easy to think that it must be down to the very way that the core application is written, this is rarely the case.

On the whole, it is down to ISVs trying to be all things to all versions of Windows, providing installation routines that try to create an application that will run on anything from Windows 98 upwards.