Summary. Security updates released on and after July 6, 2021 contain protections for a remote code execution vulnerability in the Windows Print Spooler service (spoolsv.exe) known as “PrintNightmare”, documented in CVE-2021-34527. After installing the July 2021 and later updates, non-administrators, including delegated admin groups like ...

Follow these steps to automatically diagnose and repair Windows security problems by turning on UAC, DEP protection, Windows Firewall, and other Windows security options and features. Select the Download button on this page.

The Program Install and Uninstall troubleshooter helps you automatically repair issues when you're blocked from installing or removing programs.

The tool removes malicious software from an already-infected computer. Antivirus products block malicious software from running on a computer. It is significantly more desirable to block malicious software from running on a computer than to remove it after infection.

Microsoft is aware of new variants of the class of attack known as speculative execution side-channel vulnerabilities. The variants are named L1 Terminal Fault (L1TF) and Microarchitectural Data Sampling (MDS). An attacker who can successfully exploit L1TF or MDS may be able to read privileged data across trust boundaries.

Turn Windows Security on or off. When you get a new device and start up Windows 10 for the first time, the antivirus protection that comes installed with the device is your default security app. However, Windows Security is pre-installed and ready for you to use at any time.

The Microsoft Defender Offline scan will automatically detect and remove or quarantine malware. Learn how to remove malware from your PC. Use Microsoft Defender Antivirus in Windows 10 or Windows 11 to scan your PC for malware, viruses, or other threats.

If some Windows functions aren't working or Windows crashes, use the System File Checker to scan Windows and restore your files. Though the steps below might look complicated at first glance, just follow them in order, step-by-step, and we’ll try to get you back on track. Run the System File Checker tool (SFC.exe)

Office 2021 and Office LTSC 2021 are the next perpetual releases of Office. They include improvements over Microsoft Office 2019 and earlier versions of on-premises Office. For more information, see the following frequently asked questions. General.

Solve problems with detecting and removing malware with Windows Security, including incomplete scans, detection errors, and persistent malware.