Update Fail 8024a000
Windows 8.1 Update can update Windows Defender, but all other updates fail with 8024a000.
I ran the Troubleshooter several times. Every time it said it fixed the same set of problems it said it fixed the previous time it ran.
I stopped three services, renamed two directories. re-registered some DLLs, and restarted the services according to https://answers.microsoft.com/en-us/windows/forum/windows_other-windows_update/windows-update-error-code-8024a000/562845f3-78d5-42a0-bed5-e3fd39f01df7 .
I ran Windows Update immediately after that, and it failed. I repeated all that, rebooted, ran Windows Update agaihn and it failed again.
Re: Update Fail 8024a000
The troubleshooting steps in the mentioned forum thread are quite thorough. Maybe it is now time to open a support ticket and have a support engineer take a look? Also, on https://answers.microsoft.com/en-us/windows/forum?sort=LastReplyDate&dir=Desc&tab=All&status=all&mod=&modAge=&advFil=&postedAfter=&postedBefore=&threadType=All&isFilterExpanded=false&page=1 there might even be better technical support.
However, note that since Windows 8.1 is in extended support you might not be able to use the support incident you may get as Partner for opening a ticket.