That's because scanning all accessible files on networked devices takes a lot longer and eats up much more processing power than just scanning the system's own drives.Īs one of Born's readers pointed out, you also don't want multiple machines on the same local network scanning each other's files at the same time and slowing down network traffic as a result.

Ironically, Microsoft recommends that network scans be disabled by default. Later on March 23, Born reported (opens in new tab), and Bleeping Computer (opens in new tab) confirmed, that the issue is a result of network scans - i.e., of files not directly present on the computer, but linked to via the local network - being disabled in Windows Defender. Update: How to stop the messages from appearing Instead, you might want to look into using one of the best antivirus programs for your computer until Microsoft resolves the problems with Windows Defender. You could roll back Windows 10 to before the March security patches, but we don't recommend that as Microsoft did fix a lot of severe flaws with that update. But Microsoft hasn't acknowledged the problem, so what's causing the error and whether its being worked on is unknown.Ī Reddit thread (opens in new tab) discussing the issue began on March 10, as did a couple of threads (opens in new tab) in the Microsoft user forums (opens in new tab).

This issue may have started with a Windows March patch, released March 10th, 2020. Guenter Born (opens in new tab), a German tech blogger who reported the issue a few days ago, told Bleeping Computer about 20% of his readers said they didn't have the problem, but 80% did. However, it found discrepancies in which Windows Defender Antimalware Client versions the issue is being reported under.īleeping Computer also said the error isn't impacting all Windows Defender users, even those using the same Windows Defender Engine Version. If you don't have any exclusions assigned, though, all your files should be assessed by Defender when you initiate malware scans. But that's not's happening.īleepingComputer was able to recreate the message while performing malware scans in Windows 10. You can assign Windows Defender to skip or exclude certain files on your device during scans.

Quick scan windows 10