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Refer the below info.
Tablet Support:
Microsoft Surface Pro 3, with external Type or Touch keyboard
The external Type or Touch keyboard is required for preboot authentication on the tablet. The keyboard can be detached once the user authenticates.
Drive Encryption is not compatible with the Microsoft Windows BitLocker Drive Encryption feature. BitLocker is enabled by default.
Note: You must disable BitLocker to use Symantec Endpoint Encryption functionality on tablet computers.
Refernce: Symantec Endpoint Encryption Client, version 11.0.x - System Requirements
http://www.symantec.com/docs/TECH224480