Nope, not necessary, I understand.
A BSOD (Blue Screen of Death) is another thing all together. Not something you want to see either.
First things first, before proceeding....
Do you have a good backup of all your critical data?
Do you have a known good Disk Image of your hard drive?
IF so then, you may want to just download the 1511 November Update Build 10586, in the form of an ISO from here.
Save it to a folder on your desktop or elsewhere on your computer.
When the download is done simply double click the ISO (which will mount it as a virtual drive on your computer) and run setup.exe from there to perform the in-place upgrade from that local source.
You may have (in the root of your C:\ drive) a file named something like $WINDOWS.~BT (or similar) that is the file that MS has downloaded to your computer to facilitate the upgrade. The file may be corrupt and preventing you from upgrading through Windows Update utility.
Obtaining the ISO and using that ISO as a local source for the install should circumvent the need for that other downloaded file.