WUpdate KB4343900 fails with error 80073701

Did you reboot?
Please post the log FRST.txt created after clicking fix.

Registry entries (keys or values) that are taken from FRST log and included in the fixlist to be deleted, will be deleted. FRST has a powerful deletion routine for keys and values. All the keys and values that resist deletion due to insufficient permissions or null embedded characters will be deleted. The keys that resist deletion due to access denied will be scheduled for deletion after reboot.

Nic,
I have rebooted, and the suspect keys are gone.
Trying to install KB4343900 with DISM++, I get a 'Successful' OK box, but the status is failed. In history, it says "Not applicable" for state.
Trying to install with WU, fail with same error. Running CheckSUR (again) now.

Another failed install, here is CBS log

Yes, I figured you didn't reboot.
CheckSUR.log is clean.
Will be going over CBS.log, thank you.
Need to take a look at WindowUpdate.log It's in C:\Windows Would you please upload it.

Here's a batch file uninstall_KB_.zip extract to desktop then (right-click and choose run as administrator), it will attempt to uninstall KB2633952, KB3083992 & KB4343900
You will be prompted after each attempt, please note the message on each popup and advise. We are looking for "not installed on this computer" or similar terminology.

After that, try installing the KB4343900 from stand alone installer in safe mode.
Here's the link to Microsoft Update Catalog
Download the KB and then reboot into safe mode, by restarting computer, and immediately start repeatedly pressing the F8 key.
You want the Windows 7 x64 version, I believe it will be 2nd from bottom of offerings.
Again, please advise.

Nic

You have to use the mouse to paste into CMD.

To enable the Windows Update Service, modify the following registry key by copy and paste command below into elevated CMD and pressing ENTER:

REG ADD "HKLM\SYSTEM\CurrentControlSet\Control\SafeBoot\Minimal\MSIServer" /VE /T REG_SZ /F /D "Service"

To start the service, copy and paste the following command in the CMD window and press ENTER:

net start msiserver

The Windows Installer will be started. You can now uninstall programs using your Control Panel or an uninstaller .msi package.

Yes, that's the windows6.1-kb4343900-x64 version
If it fails again, please run the below batch file
Uninstall_KB_.zip

Thank you.
WindowsUpdate.log please.
Location C:\Windows