Microsoft Defender reportedly can cause black screen after login on Windows 10 20H2

Microsoft Defender can cause black screen after login, prevent Word from starting, and several more issues, including high memory usage on  Windows 10 version 20H2. If you are affected by these issues, running the signature update and reboot may help you.

Microsoft Defender black screen after login on Windows 10 20H2

The German website BornCity reports that this unusual Defender behavior was first spotted in early April 2022. There affected systems by that time were Windows Servers with Microsoft Defender for Endpoint.

By that time, a signature update resolved the issue. It reduced the signature database file size which was quite large. A smaller file eliminated the bug.

However, it now appears that the full suite of those issues is affecting regular client versions of Windows 10, specially 20H2.

  • Black screen after login (2 minutes and longer) and goes away at some
  • Word is not opening or takes a very long time
  • Event viewer seem stuck loading events (remote and local)
  • The diagnostic performance log shows indicate very long startup times

So, it can be just a bug in Microsoft Defender. As figured by the source, the following sequence will work as a temporary workaround.

Fix black screen after login on Windows 10 20H2

  1. Open PowerShell.
  2. Type Update-MPSignature.
  3. Even there is no signature update for Windows Defender, this should fix most of the issues.

Finally, restarting Windows 10 will free up the hardware resources captured by Defender (via BornCity).

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Author: Sergey Tkachenko

Sergey Tkachenko is a software developer who started Winaero back in 2011. On this blog, Sergey is writing about everything connected to Microsoft, Windows and popular software. Follow him on Telegram, Twitter, and YouTube.

One thought on “Microsoft Defender reportedly can cause black screen after login on Windows 10 20H2”

  1. Hello. Thank you for sharing this. It’s been quite beneficial to me, and I hope it will be beneficial to others as well. Because it happened to me as well. Now it’s all fixed.

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