Blue screen error in Windows 7 or Windows Vista after installing Symantec Endpoint Protection version 11 RU5 Application and Device Control
Blue screen errors, particular during Windows startup, after installing or upgrading to SEP 11 RU5 including Application and Device Control (ADC)
For a short time during Windows 7 or Windows Vista startup, some system environment variables are not initialized. If an ADC rule includes such an environment variable the rule cannot expanded correctly. As a result, this rule will block certain startup processes and the BSOD occurs. This is fixed in SEP 11 RU6.
Upgrade to SEP 11 RU6.
Workarounds (if not upgrading to SEP 11 RU6)