I was on my sister's laptop last week as Windows decided to update itself. It said that it was "getting things ready" and was on 0%. She wanted to use the thing, so I left her to it. Some time passed and I asked her was it working. There was disk activity going on so I left her to get on with what she was doing. I had some stuff I needed to do so did that and went back to get some lunch. I asked her was it working and she replied "No.". It had been stuck on getting things ready for almost 2 hours. I switched the laptop off a couple of times and rebooted, then ran WU again.
"Getting things ready 0%". I decided to switch it off again and went here: http://www.catalog.update.microsoft.com/Home.aspx having made a note of the offending update. I then proceeded to download the cumulative update. Edge asked the question "Run, Save or Cancel", so I hit Run. Nothing happened. No download, no progressing %age, nothing.
The fix: I went into task manager then services, found 2 Windows Update services and stopped them. I then went back into Edge, and successfully downloaded the CU standalone, but saved it instead of running it. I went back into task manager, restarted the 2 WU services and ran the CU standalone, which finally worked. I restarted the machine and ran WU. "Pending download" was followed by "Getting things ready 0%" for about 2-3 minutes even though it was successfully installed on the updates list. Eventually it said everything was up to date. What should've taken 20 minutes tops took over 2½ hours.