Windows Defender bug may fill your hard drive with thousands of files

[willtech]

Microsoft strikes again.... Windows Defender bug may fill your hard drive with thousands of files. We have just had it on some devices and servers:

 

https://www.ghacks.net/2021/05/05/windows-defender-bug-may-fill-your-hard-drive-with-thousands-of-files/

https://www.bleepingcomputer.com/news/microsoft/windows-defender-bug-fills-windows-10-boot-drive-with-thousands-of-files/

 

Our Backups are taking longer as a result.

 

The affected engine version is 18100.5

Edited May 6, 2021 by willtech

[willtech]

engine version 18100.6 fixes the issue via Windows update.

[Koldov]

We have version 1.1.18100.6 so hopefully all good, but it seems within the last few weeks I am seeing a lot of failed installs for Defender...

 

This failed for us today on some laptops:

 

KB2267602 (Version 1.339.373.0) - Definitions Update

 

And this failed yesterday:

 

KB4052623 (Version 4.18.2104.10) - Antimalware Platform Update

 

These are just the latest, as I said we've had quite a few fail recently but I can't remember the last time we had a problem with Defender previously...

 

I suppose unless you check the versions everyday (they release multiple a day sometimes) you wouldn't really even know, it's just because they show up in WSUS as failed.

 

They seem to sort themselves out in a day or so (probably when the update is superseded), but then a week later it happens again!

Edited May 11, 2021 by Koldov

[willtech]

We have seen some doing the same as well. KB4052623 (Version 4.18.2104.10) - Antimalware Platform Update looks like it starts to clean up the files in the scans history folder.