This is a modification of the file to support skipping pre-provisioning of BitLocker during Windows PE without error. Otherwise, the script will run to an error point (essentially saying "the OS doesn't support BitLocker" and quitting then). Net effect is the same - this just cleans up the error messages a bit.

This goes into the script around line 150 (MDT 2013 Update 1 version), adding a new clause to the If statement.

If (oEnv("SystemDrive") = "X:") and (UCASE(oEnvironment.Item("BDEDisablePreProvisioning")) <> "YES") and (UCASE(oEnvironment.Item("DoNotCreateExtraPartition")) <> "TRUE") then ... 
    Main = Success
    Exit Function

'****** INSERTED CODE BELOW
ElseIf (oEnv("SystemDrive") = "X:") and (UCase(oEnvironment.Item("BDEDisablePreProvisioning")) = "YES") Then
    oLogging.CreateEntry "Pre-provisioning of BitLocker in Windows PE has been skipped due to BDEDisablePreProvisioning=YES", LogTypeInfo
    Main = Success
    Exit Function
'****** RETURN TO ORIGINAL CODE

Else
    oLogging.CreateEntry "This script is not currently running in Windows PE", LogTypeInfo
End If