I’ve been using Windows 7 (SP1, 64-bit). I use it rarely, and keep it very very close to factory-standard state. I use it to run Adobe FrameMaker and nothing else. I frequently run Windows Update.
But yesterday, Windows Update failed with an error code 80246002 (which I gather is in hexadecimal). None of the remediation options offered in the Windows Update succeeded; no further information was available. The Windows Update troubleshooter was unsuccessful in clearing the problem.
There are several relevant pages among the Microsoft Developer Community pages (for example, this one).
I did two things. I reconfigured DNS lookups to 188.8.131.52 and 184.108.40.206 (Google public DNS resolver, see also Wikipedia). Also, I downloaded and ran the appropriate System Update Readiness Tool (KB947821) appropriate for my system. One or both of these acts resolved the issue on my machine.
The incident should point out to Microsoft that system update machinery should be very very carefully checked. If Microsoft breaks the update machinery, how do they execute the update to fix it?