When adding a file hash manually on the Advanced Threat Protection (ATP) console, the Symantec Endpoint Protection (SEP) System Lockdown and Application & Devices Control (ADC) feature do not honor their policies.
No error messages are displayed on the SEP client
Advanced Threat Protection (ATP) 2.0 or newer
Symantec Endpoint Protection Manager (SEPM) 12.1.X or newer
Symantec Endpoint Protection (SEP) 12.1. or newer
This issue might occur if you manually add a file hash (MD5 or SHA 256) to the ATP blacklist in uppercase.
This issue is resolved in Symantec Endpoint Protection (SEP) 14 MP2. For more information on upgrading, please see Upgrade or migrate to Endpoint Protection 14