How can I prevent Microsoft Security Essentials from performing its automatic scan after booting system?

Question

I have a Vista SP2 system with MSE installed. Right after booting, MSE automatically does a quick scan which significantly slows down my system until it has finished scanning. I would like for MSE to be enabled upon startup so that it can just perform real-time monitoring, but let me manually choose when to perform the scan, so as to not bog down my system after booting. I used a resource decompiler tool to inspect msseces.exe, MsMpRes.dll and MsMpEng.exe's resources and saw an XML resource which had several parameters, but could not locate the parameter which tells the engine to automatically scan after bootup.

Answer 1

By default, MSE is not supposed to run a scan each time you boot. It is possible something is removing your scan history which causes MSE to think you haven't performed a scan at all.

Here is information I found at Microsoft Answers, which I found helpful.

Are you using CCleaner? Piriform has programmed it for some reason to remove part of the MSE History files and it's deleting the files MSE checks to determine the last time a scan was conducted.

Answer 2

MSE does not automatically perform a scan at boot (or any other time). In fact, the scheduled scan settings in MSE do not even allow for specifying a scan to start at boot. It is possible that someone created a task in Task Scheduler to do that, and if so, you can alter or delete that scheduled task.