See title. (I'm on Windows XP) Ever since I bought this computer, EVERY single piece of security software has had at least once a very negative effect on my security, which includes the functionality of the hardware, software, and services. I mean this in a very broad way. A program disconnecting me from the internet, negatively affecting another security program, freezing my computer, repeated crashes from which I could only recover by spending a lot of time and effort, destructive interaction with the operating system, offering insufficient antispyware protection, and a lot more. I'm talking about big issues, not minor ones. The only exception that I have encountered was Counterspy, although I must admit that updates can be a problem ... So I'm not sure if it is an exception ... The smallest exception maybe ... Examples: McAfee, Pctools software, the Spy Sweeper, Kaspersky, Panda, to name a few ... Feel free to include your imaging software/hardware combo if this applies ... After my latest problem with the Spy Sweeper I'm beginning to think that every option is insecure or places an unacceptable burden on computer performance/computer use. You may think you have an exception, but maybe it only takes time for your particular approach to become a problem. One is tempted to go 'naked', but this is not without risk either.