Dear Farzad,
When I want to install the Unmannaged version, we have three choices: remove,repair,modify
and agian for each action we do need password.
Dear Prachand,
the registry key is already 0, and when change it to 1
after restarting the SMC service the key becomes 0 again
and this will not help.
but I did "Mohammad Altaf Khan" advice:
"Try in Safe mode.
stop all Symantec services and delete all Symantec registry.
in
HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Symantec Endpoint Protection
then use Cleanwipe."
it seems it does work, but I need to check it on another system and I will inform you..
Thanks all.