HI all! I found this article when I ran into this problem on my Mac Mini Late 2018, trying to update from 11.0.1 to 11.1 and I tried all the different suggestions in here. Both downloading the full Install file as well as trying to do the update from "System Preferences", both in "Regular" and "Safe Mode". Always stopping partly through with different text on the status indicator window. What helped me in the end was that I tried something that I encountered when trying to setup my MacBook with Big Sur to do Time Machine backups to my Synology NAS which was failing, and the solution was to uninstall Sophos Home (mentioned in a few places, but also in Sophos support article called "Support for macOS 11- Big Sur"), and it's apparently a bug somewhere (either in Mac OS or in the Sophos software) that limits the possibility to use a Network Share for Time Machine backup. So I just, basically because everything else failed, tried to uninstall Sophos Home, and "Bob's your uncle...". I was able to install the update as supposed to. Hope this helps someone else as well!! Cheers, Jonas