Nowadays, Ransomware, like WannaCry, is making more buzz than typical malware. In fact, AV-Test, an independent IT-security organization, has found the same issue. Although it is unusual, you might encounter this problem from time to time. Although Microsoft Defender has made some improvements regarding this issue, it is still not 100% gone. There is only one reason – it scans the websites and files before moving them to another drive or computer. When you have an antivirus installed on your computer, it might slow down the data transfer speed and internet browsing.

Previously, on Windows 7, it used to take more than 7 minutes to finish the scan.

In that 2.5 minutes, it scanned around 40K files, including some software, documents, etc. It took around 2.5 minutes to scan a 32GB USB drive containing more than 15GB of data while testing in real life. The Full Scan takes more time than a Quick Scan, but both are really fast and comparable to the industry standard in the latest version of the Security Suite. However, things have changed or improved a lot over time.

Previously, Windows Defender used to take a long time to finish scans even if you have a small USB drive or partition.

Defender for windows 10