I came across an HP unibody laptop which was caught in a Windows 10 reboot recovery startup loop. Unable to complete an SFC scan I discovered a DISM command which will trash any pending disk actions and in this case allowed the system to boot to the login prompt (after throwing away a number of Windows updates).

dism.exe /image:C:\ /cleanup-image /revertpendingactions

How to Fix SFC /SCANNOW There is a System Repair Pending