Unable to unmount volume for repair

Number:rdar://37473566 Date Originated:12-Feb-2018 10:26 pm
Status:Open Resolved:
Product:macOS + SDK Product Version:10.13.x
Classification:Crash/Hang/Data Loss Reproducible:Always
10.12.6 Mac, updating to 10.13.x (10.13 - 10.13.3 tested) fails with one or two errors, this is for the error “Unable to unmount volume for repair”.

Steps to Reproduce:
10.12.6 macOS, attempt update to 10.13.x via the “Install macOS High Sierra.app”.

Expected Results:
macOS High Sierra installs successfully.

Actual Results:
Mac reboots into the installer, requesting FV2 authentication before, then fails during install attempts.


Following restarts can give the error “OSInstall.mpkg is missing or damaged” & some items are left at “/macOS Install Data/“


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