Uninstall that KB update from Add/Remove Programs. Turn off Automatic Updates then goto the Windows Update web site using your Windows Update link in the Start Menu > All Programs list at the top of the list.

Let Windows Update scan your system and recommend any critical/security updates. This should include the Malicious software removal tool. You can hide any other updates you don't want to download/install.

Download that one and once it is installed and completed, re-enable Windows Update in your Security Center. Hopefully that will reset the log.

An alternative if you would prefer not to uninstall any updates is to simply visit the Updates website and let it scan. If it recommends that KB update again, hide it.

See if one of those works.

Mark