Got an issue this morning with the latest update for Windows Defender (1.299.2640.0) Patch ID 400009 "Download Success but checksum failed" on workstations.

Checking the patch, it says it failed to download, "Download blocked by firewall/antivirus. Enable firewall configuration or exclude antivirus to allow download", however there is a 400009-mpam-fe file in the store of 110 MB size. I've tried deleting and re-downloading but this hasn't helped.

I've checked the firewall and antivirus, this is not the case and I can download the file manually. however when trying to upload it into DesktopCentral, it says "The upload has failed due to checksum error. Choose a valid file", so even manually it doesn't accept it.

Looking online, I go to the Microsoft site and it's showing a download for version 1.299.264 7.0 (Released: 8/23/2019 8:20:11 AM) which is a later version.

I've tried running a manual update of DesktopCentral, that didn't find anything to download.

I think DesktopCentral is getting confused, maybe trying to match a checksum of what is now 1.299.264 7.0 to the download which is 1.299.2640.0 and failing, please resolve.

Have emailed support as well as posting on here.