This article details how to add a passphrase user to the User Access list for Symantec Drive Encryption.
Windows - Single Sign-On user
If you choose the Use Windows Password option, after initial encryption, use your Windows password when the PGP BootGuard screen is displayed at the start of booting. The PGP Single Sign-On (SSO) feature logs into Windows for you only need to type your passphrase once.
Create New Passphrase user