1. Going back to your original post, what is the precise symptom of client-SEPM comm not working properly?
2. If the user will not let you on the machine how are you stopping SMC?
3. Here are two batch script lines I use to stop SMC ... starting is similar::
rem 32bit sep 11 and 12
"C:\Program Files\Symantec\Symantec Endpoint Protection\Smc.exe" -stop && echo "SMC -STOP" was applied.
rem 64bit
"C:\Program Files (x86)\Symantec\Symantec Endpoint Protection\Smc.exe" -stop && echo "SMC -STOP" was applied.
John