Security Update KB5004945 causing BSOD / Reboot Loop

Question

We have quite a few users this morning reporting their PCs getting stuck in a 'reboot loop' after installing Security Update KB5004945. They get the options to do an advanced repair, which doesn't work. This hasn't been the case for all users, but some commonalities between them are 20H2 build 19042.1052 and one with 19042.804. As the users are working remotely and do not have admin credentials, there are some limitations as to what they are able to do themselves. Does anybody have any information or suggestions on resolving this remotely or whether Microsoft are aware and releasing a new patch?

Answer 1

AbelInglis-0554 ,

1) Find a flash drive that you can format.

2) On a working computer create:

a new bootable windows 10 iso 21H1:
https://www.microsoft.com/en-us/software-download/windows10
Download Windows 10 ISO File
https://www.tenforums.com/tutorials/9230-download-windows-10-iso-file.html
Create Bootable USB Flash Drive to Install Windows 10
https://www.tenforums.com/tutorials/2376-create-bootable-usb-flash-drive-install-windows-10-a.html

3) Boot using the bootable Windows 10 iso:

post images for any startup repair error messages or codes

post images for any system restore error messages or codes

4) Type these commands and post images of the commands with results:

a) bcdedit /enum all

b) bcdedit | find "osdevice"

(record the partition drive letter)

c) dism /image:W:\ /cleanup-image /revertpendingactions

(replace W with the drive letter partition displayed in the prior command result) (typically C or D)

5) reboot

6) reopen command prompt if the computer cannot boot to the desktop

7) Type these commands and post images of the commands with results:

a) dism /image:W:\ /get-packages /format:list
(change W: to the partition drive letter displayed in the above command)

b) wmic qfe list

search for:

srttrail.txt
%systemroot%\Minidump
%systemroot%\memory.dmp
%systemroot%\LiveKernelReports
%windir%\Logs\CBS\CBS.log

C:\WINDOWS\Logs\CBS\CBS.log
C:\Windows\memory.dmp
C:\Windows\Minidump
C:\Windows\LiveKernelReports

Post share links for any of the above files if < 2GB.

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Answer 2

There is not a BSOD or reboot loop related known issue on Microsoft KB5004945 document, only input, Edge and printer related known issue.
https://support.microsoft.com/en-us/topic/july-6-2021-kb5004945-os-builds-19041-1083-19042-1083-and-19043-1083-out-of-band-44b34928-0a71-4473-aa22-ecf3b83eed0e
So the reboot loop issue on a few users is just an individual phenomenon, don’t need to worry about.
Maybe there is a third-party software conflict or driver compatibility issue on those users’ devices, you could compare their devices with other normal devices. Or just enter WinRE to uninstall KB5004945 or restore system to a healthy timepoint, once boot normally, pause update for 7 days, wait for another new update from Microsoft.

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