Windows Update doesn't work on Window 8.1

I had the identical problem. The problem is that the Windows Update Agent is out of date and does not update itself first as it is supposed to do.

To fix this you first download the most recent Windows Update Agent for your OS:

• Windows 8.1: https://support.microsoft.com/en-us/kb/3138615
• Windows 7: https://support.microsoft.com/en-us/kb/3138612

Note: Microsoft support kept referencing an outdated page for kb949104 which is NOT the most current WU Agent.

To update the Windows Update Agent:

• Open an elevated command prompt.
• Stop the Windows Update Agent by typing net stop wuauserv and hit Enter.
• Run the installer you downloaded earlier.
• Start the service by typing net start wuauserv.
• Restart your computer.

Windows 8.1 should now update itself and then you can run the W10 update. It may take a few days and a few restarts for W8.1 to fully update but you should start seeing results in the Window update history file.

You can try manually installing the updates but i found it best to just leave the machine on for a couple of days and restart as requested, and let it do its own thing.

It would be very nice if the Windows Update Agent actually updated itself, but it doesn't sometimes, and so you have to go through all this to make it work the way you expect it to.

Very important to Joel's answer is, that sometimes stopping wuauserv is not sufficient. I had to set Windows Update to Never check for updates (not recommended) and then reboot. Without this i can't even install KB3138615 MSU on fresh Windows 8.1.

In my case proper instruction was:

• Set Windows Update to Never check for updates (not recommended)
• Reboot

• Download installer update:

  • Windows 8.1: https://support.microsoft.com/en-us/kb/3138615
  • Windows 7: https://support.microsoft.com/en-us/kb/3138612

• Install update

• Reboot

Then check for updates works perfectly.

Just wait a bit.

Over the past two/three months, this has been happening on Windows 7 and Windows 8.1 systems for me (around 30 PC's over the two months). Sometimes it takes 2 hours to find updates, sometimes it takes 24 hours. Just leave it checking for updates.

If you are on a time limit for some reason (like I sometimes am), or you want to try and speed things up, I use this tool. It will download the updates (directly from Microsoft, not through the update client). You can then save this and use it in an offline scenario.

Try Windows Update Troubleshooter for Windows 7/8 as described by Microsoft here, and then check for updates again. It resets windows update and fixes problems due to damaged or not properly configured Windows Update infrastructure.