Changes

* /o - don't automatically run the updater and the system scan after installation - when you then login it may then give a red indicator and say that real time protection is off because virus definition files are out of date. I've had a few differing experiences at this point, either it updates them quickly automatically, or if you click on the system tray icon it tells you it's out of date but then updates it quickly, or it displays this then just waits for you to manually press the 'Update' button.. This is as both an Administrator and as a Limited User.

Soon after installation it MSE can recognise potentially useful software as a threat. For example if you have UltraVNC installed it will flag up UltraVNC.exe and RealVNC.exe. There's a risk that a user, when prompted, will choose to remove or quarantine such files and remove the administrator's ability to connect. Administrative users can allow, quarantine or remove suspicious files where as Limited users can only remove or quarantine suspicious files. Administrators will want to white-list any such programs that should not be considered a threat, upon installation.

White-listing can be performed manually using: Show details → Recommendation → Select an action → Allow → Apply actions (note that Close means 'don't take any action at this point') → Close - this . This is saved system-wide.

Continuing with the above example, to allow UltraVNC , the registry file should look like this:

Virus definition updates for MSE are automatically downloaded and incorporated by the program, or via Windows Automatic Updates.

The Microsoft Security Essentials updates program itself is updated through Windows Automatic Updates.