Microsoft has published a list of programs which will either not work or will suffer from reduced functionality after the installation of Vista Service Pack 1.

The list of programs is primarily composed of security applications, such as Trend Micro Internet Security 2008. However, some other programs also feature on the list. Users are advised to install any updates from the application vendor in order to fix the problem.

"Windows Vista Service Pack 1 (SP1) contains many security, reliability, and feature updates for Windows Vista. A program may experience a loss of functionality after you install Windows Vista SP1. However, most programs will continue to work as expected after you install Windows Vista SP1," the company said.

The list is not considered to be comprehensive, and Microsoft has asked users who encounter problems with other applications to first restart their PC and, if they still encounter problems, to install a newer version of the program or contact the software vendor.

Issues of back compatibility require regression testing on old applications, making any deployment very painful to do in one install, he said. The theory is that you only have to fix it once, and then should be able to deploy this fix across your whole environment. The issue is that many organisations do not have automated deployments.

The problems with SP1 will only make backwards compatibility issues worse, especially since many companies have been waiting to deploy the operating system until the release of this Service Pack.

The positive thing about Windows Vista has been that organisations are taking a step back and reviewing their deployment methods. Because the desktop market is now maturing, the trend would have happened anyway, but Vista's problems have acted like a catalyst.