Microsoft's list of known problems caused by Windows XP SP2 at: http://support.microsoft.com/default.aspx?kbid=884130&product=windowsxpsp2 ... has several entries for various versions of anti-virus products. The descriptions are not detailed enough for me to understand whether SP2 causes inconvenience, or actually cripples. For instance, they report: that for Norton AntiVirus: At system startup, Scheduled Tasks in Norton AntiVirus 2003 does not automatically scan. Separately I've heard that you cannot get a patch from Symantec to fix this; they will only issue SP2 patches for AV 2004. Any real-world experience with how badly SP2 breaks various levels of various products would be useful. This page: http://www.symantec.com/techsupp/enterprise/sp2/faq.html ...seems to indicate the failure is a false positive: Q: Will Symantec software be compatible with Windows® XP SP2? A: Yes, although one feature of Service Pack 2, the Windows Security Center, may indicate otherwise. By design, Symantec includes tamper-protection features to make it difficult to scan the status of its products. As a result, the Windows Security Center can detect the presence, but not the status, of some Symantec security software. Symantec is developing an update to ensure that the Windows Security Center shows the status of Symantec products as green (on). This update will be in the form of a product update for some products and as a Maintenance Release for others. The schedule for updates and Maintenance Releases appears on the the Product Update tab. Thanks, /rich