Windows 7 Service Pack 1 can't be installed : ERROR_SXS_ASSEMBLY_MISSING(0x80073701)

Question

How to install Windows 7 (6.1 to be exact) Service Pack 1 (KB976932) if it ends with the following error:

ERROR_SXS_ASSEMBLY_MISSING(0x80073701)

"System Update Readiness Tool, October 2014" (KB947821) installed too, made no difference.

Edit 1: these commands have been run and did not fix the problem:

sfc /scannow
chkdsk /f /v /r /b

The solutions pointed out on these articles did not fix the problem, and needed to be reverted using System Restore:

Edit 2: following instructions of Steps to follow before you install Windows 7 SP1 [...] from the Microsoft Download Center :

Windows is activated;
the activation is original;
no malware found by MalwareBytes 4.3.0;
antimalware software uninstalled;
confirmed that KB2454826, KB2534366, and KB2533552 were already installed;

Edit 3: uninstalled manually all updates that I could, leaving only these that cannot be removed:

Then, did the following commands:

net stop wuauserv
cd %systemroot%
ren SoftwareDistribution SoftwareDistribution.old
net start wuauserv

This also did not help.

Comments are not for extended discussion; this conversation has been [moved to chat](https://chat.stackexchange.com/rooms/138715/discussion-on-question-by-bsaxubx5koqdepcaqsffwgy554psah-windows-7-service-pack). — DavidPostill, Aug 23 '22 at 17:05

harrymc · Accepted Answer · 2022-08-25T13:24:26.133

1

You are getting error code 0x80072EFE when trying to install any Windows update.

This error means that your computer can't contact the Windows servers. Windows 7 is long out of support, but security updates will be available for it through at most January 10, 2023. It can also mean that your computer's date & time are very wrong (which is probably not the case).

I think that the problem stems from the fact that your Windows 7 setup is simply too old to manage to contact the Windows servers, so you cannot install updates. On the other hand, yours is not a fresh installation, so simply installing SP1 from a file doesn't work either.

I suggest to install Windows 7 from scratch, then apply SP1, as described in this answer of mine that worked for several people. Or, if you can get a Windows 7 ISO that already contains SP1, then you can skip the step for installing SP1.

You should of course save your data before the installation and check the disk's SMART attributes to see that it's fine (assuming that it's recent enough to support SMART). I would also suggest, while installing Windows 7, to format the disk with a slow (not quick) format, to better check the disk sectors.

(I will spare you the usual warnings about not using such an old Windows version.)

edited Aug 25 '22 at 13:24

answered Aug 23 '22 at 18:34

harrymc

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Your reply is very helpful, thank you. You correctly pointed out that the `ERROR_SXS_ASSEMBLY_MISSING(0x80073701)` derives itself from `0x80072EFE`, which, in turn, derives itself from Windows 7 not having the SHA-2 cyphers unless it has SP1 installed. Without modern cyphers, Windows 7 cannot contact correctly Microsoft Update servers and download all the required prerequisites for SP1, which I'm unsure which ones would be, as they are many. – BsAxUbx5KoQDEpCAqSffwGy554PSah Aug 24 '22 at 12:55
After SP1 is installed, the convenience rollup will install these hundreds of patches in one go. – harrymc Aug 24 '22 at 14:04
@Ramhound I was just affirming, with other words, that harrymc answer was technically correct and complete. I was not arguing with him, I accepted his answer. As you suggest something else, would you like to provide another answer for the question? I believe that debating your suggestion on the comments would derail his answer. – BsAxUbx5KoQDEpCAqSffwGy554PSah Aug 25 '22 at 13:18
I added to the answer the possibility of using an ISO that already contains SP1. – harrymc Aug 25 '22 at 13:25

Windows 7 Service Pack 1 can't be installed : ERROR_SXS_ASSEMBLY_MISSING(0x80073701)

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