My Windows started to have similar problem yesterday. The Windows Security Center showed Windows Defender is out of date. but after mannual update, I received a message: "There are no new definitions available to download for Windows." In Windows Defender, it states Real-time protection is on and Definition version is 1.43.73.0 created on 9/4/2008. I have tried Mohit Kapoor's solution, but have some problem as Grich had. After I run winmgmt/verifyrepository, system responded "WMI repository is consistent". "Hornet" wrote: > I have Windows Defender running normally on Windows Vista (the task-bar icon > is showing that Defender is on and running ok) but the Security Center is > telling me that Windows Defender is turned off and there is a button to turn > it on. However, when I press the Turn On button (even though I know it is > already turned on) I get the message: "Security Center is updating > definitions for Window Defender". After "searching for definitions" I get > the message: "There are no new definitions available to download for Windows > Defender". I'd like to solve this because the Security Center icon is always > showing me that I have a Security Alert.
