Update failed with 0x80010108 but most of my disk space is gone

I'm running Windows 10 version 1709, on a laptop that has been off for a year or more. I turned it on and let it download updates, only to see in update history

Feature update to Windows 10, version 1803 x64 2019-10B (2) Last failed install attempt on ‎21/‎10/‎2019 - 0x80010108

Windows has not notified me of any attempted or failed updates, I had to go and look. Meanwhile, I note I've lost about 8Gb of very limited disk space. Am I going to get this back? Is Windows going to notify me of the issue or just sit there pretending everything is fine?