This policy setting allows you to configure catch-up scans for scheduled full scans. A catch-up scan is a scan that is initiated because a regularly scheduled scan was missed. Usually these scheduled scans are missed because the computer was turned off at the scheduled time. If you enable this setting, catch-up scans for scheduled full scans will be turned on. If a computer is offline for two consecutive scheduled scans, a catch-up scan is started the next time someone logs on to the computer. If there is no scheduled scan configured, there will be no catch-up scan run. If you disable or do not configure this setting, catch-up scans for scheduled full scans will be turned off. Counter Measure: Configure this setting depending on your organizations requirements. Potential Impact: Scanning can impact performance. Fix: (1) GPO: Computer Configuration\Administrative Templates\Windows Components\Windows Defender\Scan\Turn on catch-up full scan (2) REG: HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Windows Defender\Scan!DisableCatchupFullScan