On Sunday, my computer kept informing me about updates to install on the login screen, but when I open Windows Update, there aren't any. If I manually checked for updates, one update for Windows Defender appeared, but it's already been installed, so trying to install it causes it to fail. (The error I got in the event log was 0x80070643, but Windows Update reported either 80096010 or 8050800C.) Even though Windows Defender is up to date, it still won't stop offering the definition update that's already installed. I wanted to get everything fixed before Patch Tuesday, which is...today. Luckily, I got everything solved on the same day. Everybody's got a different solution to the problem, but here's what I tried: The first thing I tried was to restart the computer. "Turn it off and back on again" is one of the most basic troubleshooting techniques. I guess it was too basic because it didn't work. Next, I tried just downloading the full-blown definitions manually and installing them that way. The definitions were already up to date, but maybe this would make Windows Update see the change. Running the file did nothing, assumedly because it was the same version. When I ran Windows Update, the same update appeared and failed to install. I tried the Network Inspection System update at the bottom of the same page. That didn't appear to do anything either. I checked for updates again and it didn't show the update anymore. That's what worked for me, but I assume those errors could appear for any number of reasons. Of course, when the Patch Tuesday updates show up on my computer, I hope that they install normally. If I write another one of these entries, then it didn't.