Although Windows Defender includes a real-time scanner that constantly monitors files and folders for threats, it’s always a good idea to regularly scan your computer…just in case. Unfortunately, Microsoft omitted a dedicated scheduler in Windows Defender, even though its predecessor, Microsoft Security Essentials, logically included one, as do most other anti-virus programs. Therefore, most Windows 8 users either neglect regular scanning or choose to manually start them. However, there is a better way.
Windows 8’s Task Scheduler at least picks up Windows Defender’s slack by allowing users to schedule a myriad of tasks, including automating scans. This less-than-intuitive approach might require a little guidance, however, because the procedure goes beyond toggling a scheduler on or off.
Scheduling Regular Scans
1. Press “Win-R” to open the Run dialog, type “taskschd.msc” without quotes and press “OK” to run Task Scheduler. If you receive a User Account Control warning, click “Yes.”
2. Open the folder “Task Scheduler Library/Microsoft/Windows/Windows Defender” in the left pane and then double-click “Windows Defender Scheduled Scan” in the upper middle pane.
3. Select the “Triggers” tab and then click the “New” button.
4. Select “On a Schedule” from the top drop-down menu and choose your preferred scheduling method. “Daily” schedules a same-time daily scan. “Weekly” schedules scans for one or more days of the week. “Monthly” schedules scans on selected months and can be configured to scan on specific days of the month, such as the 1st and 15th, or relative to weeks, such as the first Monday of the month. Verify “Enabled” is checked and click “OK.”
5. Select the “Actions” tab and double-click the “Start a Program” entry.
6. Type “Scan -ScheduleJob -ScanType 2” in the Add Arguments field. Adding this text forces Windows Defender to override the default quick scan to instead perform a full scan. If you prefer a quick scan, keep the default “Scan -ScheduleJob” text. You also need to add quotes around the path in the Program/Script field or click “Browse” and select “MpCmdRun.exe,” so the quotes automatically appear. Curiously, the default value omits the necessary quotes; in fact, if you don’t add the quotes, you’ll immediately receive an error when you click “OK.” Therefore, the Program/Script field should read (complete with quotes):
“C:\Program Files\Windows Defender\MpCmdRun.exe.”
Be sure to type the entries if you’re not using the Browse method; sometimes copying and pasting the text causes problems. Click “OK” when done.
7. Select the “Conditions” tab and check “Start the Task Only If the Computer Is on AC Power” to prevent scans running down your battery when the computer is not plugged in. Click “OK.”
8. Look at the Task Scheduler Library entry to see when the next scan will be, under the column “Next Run Time.” If you ever want to disable the scanning schedule, don’t delete the entry; instead, simply click “Disable” in the right pane. To re-enable it, click “Enable.”