While working on a Windows 10 upgrade project for a company, it was observed that numerous machines were failing with CRITICAL_PROCESS_DIED. A critical service would crash in the SECOND_BOOT phase between 80-90% of total progress.  This resulted in bugcheck 0xEF.  The root cause in my organization was the value of MachineLaunchRestriction being abnormally large.  It was larger than 65535/FFFF.

To determine your value, you can use PowerShell: 

Above is the output of the PowerShell.  The value of MachineLaunchRestriction is outlined in red.  If your output is larger than 65535, you can remediate by running the following PowerShell:

# Set Variables

$dir = Test-Path – Path C:\regbu\ole

# Make Directory if it doesn’t exist

if(!$dir){
mkdir C:\regbu\old
}

# Backup Registry in case it hits the fan

reg export “HKEY_LOCAL_MACHINE\Software\Microsoft\Ole” C:\regbu\ole\hklmsoftMSole.reg /y

# Delete the key /f forces this

reg delete HKEY_LOCAL_MACHINE\Software\Microsoft\Ole /v MachineLaunchRestriction /f