Can't prepare for image capture - Win10 x64 1607

I'm trying to capture a Windows 10 x64 1607 image. The "Prepare for Image Capture" task fails after 8 seconds (return code 1); following are the logfile entries that may be helpful. Thoughts?

[2017/11/08 09:06:44.481 2832:3632 0] File:ExecuteCommand.cpp,Line:4370 ERROR: Exception has occured in function ExecuteCommand.cpp() at Line No 2420. Type of exception is ExecuteClassException. Error is Default Message: Exception in ExecuteClassException. Error Description is  "Unable to create new process as user". Value of Windows error code = 740 and message is " The requested operation requires elevation.
"

[2017/11/08 09:06:44.513 2832:3632 2] DisableWow64
[2017/11/08 09:06:44.513 2832:3632 2] OS is Vista and Above using Wow64 Redirection

[2017/11/08 09:06:44.529 2832:3632 2] ExecuteCommand.cpp@4422 ExecuteClass::SetResult() - StopTaskCmdReceived = 0

[2017/11/08 09:06:44.529 2832:3632 2] ExecuteCommand.cpp:util::ExecuteClass::SetResult():4440. Value of nResult(@ReturnValue) = 1, Value of bResult(@Success) = 0

[2017/11/08 09:06:44.544 2832:3632 2] ExecuteCommand.cpp@4459 Output @errorMessage=Exception has occured in function ExecuteCommand.cpp() at Line No 2420. Type of exception is ExecuteClassException. Error is Default Message: Exception in ExecuteClassException. Error Description is  "Unable to create new process as user". Value of Windows error code = 740 and message is " The requested operation requires elevation.
"
[2017/11/08 09:06:44.559 2832:3632 2] ExecuteCommand.cpp@4468  Task have completed. Failure return!!