Microsoft was testing a tool called Standalone System Sweeper Beta, a recovery tool that can help you start an infected PC and perform an offline scan to help identify and remove rootkits and other advanced malware. In addition, Microsoft Standalone System Sweeper Beta can be used if you cannot install or start an antivirus solution on your PC, or if the installed solution can’t detect or remove malware on your PC. Now the product has crossed the testing phase and entered into beta phase with new branding. Its now called Windows Defender Offline. It almost does the same job with new UI and branding. You can download it here.