Waking up from blogging slumber simply to post about how I eventually was able to update to Windows 10 1803 (April 2018 Update) from 16XX (can’t recall exactly) after going through at least 5 failed attempts and numerous articles online. Thought it might help someone.
These particular instructions worked for me: https://www.bleepingcomputer.com/forums/t/677412/windows-10-spring-1803-update-finally-successful/. Commenting there is disabled, so here I am now.
The solution in the thread prevents the update from having a BSOD at 75% with the message “The installation failed in the Second Boot phase with an error during migrate data operation.” If that’s not your update issue, the solution may or may not be for you.
I didn’t have the exact programs like the ones described in the thread, so I simply uninstalled software that had relatively system-wide control on Windows, namely: Avast Anti-virus, Avast Safe Search, FiiO Q1 Mk II Drivers, Equalizer APO. I also disabled all startup programs.
Note that I had to run the Windows update troubleshooter described here to be able to start the update in the first place, as my old Windows installation seemed to have corrupt components.