Games, security software and popular business packages are causing major headaches to users of the new long awaited service pack for Windows XP.
Released last week, reports have started coming in of issues with over 50 programmes that Microsoft has flagged as clashing with the download.
Microsoft has had to publish a list of over 50 software titles on its knowledge base support site that it knows will cause problems when run on a machine that has had the new service pack loaded on to it.
Key contenders likely to affect pocket-lint readers are Unreal Tournament 2003, Photoshop Elements and most file sharing programs.
The problems arise from the new Windows Firewall applications which automatically installs on default and then blocks access to the internet to stop incoming attacks from viruses, worms and other security threats.
Microsoft has produced guidelines on how to fix know problems on its knowledge base support site:
Currently the Service Pack is only available to business customers, however Microsoft is hoping to offer the download to personal users through its auto update download service. Expect a notice on a PC near you in the coming weeks.