[This version of Windows Defender is still in development, so some Help information might be inaccurate or missing.]

Schedule when Windows Defender scans your computer

To complete these steps, you must be logged on as Administrator or be a member of the Administrators group.

We recommend that you schedule a daily quick scan. A quick scan will check the areas of your computer that spyware and other potentially unwanted software is most likely to infect. If you want Windows Defender to check all files and programs on your computer, run or schedule a full scan.

To enhance the security of your computer, you can choose to automatically remove spyware and other potentially unwanted software if is detected during a scan.

To schedule scans

Open Windows Defender. (Click Start, click Programs, and then click Windows Defender.)
Click Tools, and then click General Settings.
Under Automatic scanning, select the Automatically scan my computer (recommended) check box, and then select the frequency, time of day, and type of scan that you want to run.
To automatically remove spyware or other potentially unwanted software after a scan, select the Apply actions on detected items after scanning check box.
Under Default actions, select the action that you want to apply to each Windows Defender alert, and then click Save.

View the progress of a Windows Defender scan

Turn real-time spyware protection on or off

Understanding Windows Defender alert levels