Schedule when Windows Defender scans your computer

To complete these steps, you must be logged on as an 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 it is detected during a scan.

To schedule scans

Open Windows Defender by clicking Start, clicking Programs, and then clicking Windows Defender.
Click Tools, and then click Options.
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 default actions to items detected during a scan check box.
Under Default actions, select the action that you want to apply to each Windows Defender alert, and then click Save.

Notes

You can't select a default action for software with a severe alert rating because Windows Defender automatically removes it or alerts you to remove it. If software has not yet been classified for potential risks to your privacy or your computer, you must review information about the software and then choose an action.
If Windows Defender alerts you about software and you choose to ignore it by selecting Ignore in the list of available actions, you are allowing the software to run on your computer. If the software acts suspiciously at a later time, Windows Defender will alert you about the software again or automatically apply actions that you have set for each type of alert. If you trust the software and do not want Windows Defender to automatically remove or quarantine it, see Add or remove items from the Windows Defender allowed list.

View the progress of a Windows Defender scan

Turn Windows Defender real-time protection on or off

Understanding Windows Defender alert levels