I asked in the Apple community Mac OS X forum seven days ago - no answers. https://discussions.apple.com/thread/8357828
My late 2012 mac mini 6,2 16gb with 1TB fusion drive refuses to upgrade from 10.13.3 to 10.13.4 reporting "some updates were not installed. details/install".
i have tried:
1) app store upgrade
2) update combo 10.13.4
3) booted to recovery mode, ran disk repair on internal Fusion drive, which found and repaired errors, rebooted, then tried update combo (repeated verify/repair cycle no errors found, no fixes needed)
4) Disconnected two external TM drives, ran update combo
5) booted to safe mode, ran update combo
6) turned off google updater with script, ran update combo
#!/usr/bin/env bash osascript -e 'tell application "GoogleSoftwareUpdateAgent" to quit' sudo launchctl unload /Library/LaunchDaemons/com.google.keystone.daemon.plist
7) held shift during update combo reboots
8) Removed Google Updater which was filling log with lots of failed update messages
9) Level 1 Apple support: App Store Featured page High Sierra which failed with unable to unmount to perform repair.
9) More Apple Support - a couple more tries working with level 3 which is reviewing collected logs and settings, and screen shots.