Windows 10: Error Downloading Cumulative Update

Let me start this off by saying I'm not the most tech savvy so sorry in advanceI've recently noticed when I go to my Windows Update section in settings I get a red alert under saying "Your device is missing important security and quality features" Which I spent a day trying different tutorials to fix along with going into safe mode trying administrative commands with but to no avail. Then I get a notification saying I had some updates to install so I did thinking nothing of it and all but one update worked successfully that being "2022-05 Cumulative Update for Windows 10 Version 21H2 KB501394

:)

 

Cumulative December update

I tried to download and install the December Cumulative Update from the website you had listed and did not have any luck. I received error messages stating that it would not install and it still has not come through windows update. Do you have any other
suggestions?

 

Can't install Cumulative Updates for v1909

I was having a different error than you, but still could not get any updates to work without failing after download - whether through Windows Update or downloading from the Catalog and doing it locally. After trying many people's lists of how to reset Windows Update, I finally did the Repair Install Windows 10 with an In-place Upgrade Installation & Upgrade by Shawn Brink. Other than going in and turning off Defender and the Firewall just in case to speed things up when it was "Getting Ready" (this step took about 2 hours for me), this worked flawlessly. I went from a busted 19041.264, to a repaired 19041.84. I was then able to go into Windows Update, and about five updates installed perfectly including the May and June cumulative updates. Just a suggestion if you run out of ideas, I had!

 

Cumulative update KB4598242-OS Build mismatches-W10 20H2

This is what I've done to date.

1- downloaded the update reset batchfile from the source given, and run it.
2-immediately rebooted the machine
3-downloaded the relevant ssu, although this is listed as installed in Control Panel > Programs. Running that msu confirms that it's already on the system.
4-downloaded the KB4598242 msu from Microsoft, and run it. It started Ok but failed with the same error 0x8007000D
5-checked with sfc /scannow - no problems reported.

In other words, I've stepped through the suggested processes, but still end up with the update failing to install, and with the same error as when update attempted through WU.

I may try the whole process over again, before attempting anything else.