Ihave used the tool in 11.x

Can RxDefsSEP tool are woriking in sep 12.1.2?

The "Rx4DefsSEP" utility is used to completely remove and replace definitions on 32-bit or 64-bit Symantec Endpoint Protection 11.x clients. It is not intended for operation with Symantec Endpoint Protection 12.1 systems due to changes in folders and operations. The tool does not replace definitions for Symantec Endpoint Protection Manager.

Read it

Using the "Rx4DefsSEP" utility

Youbcan clear it manually

How to clear out definitions for a Symantec Endpoint Protection 12.1 client manually

http://www.symantec.com/business/support/index?page=content&id=HOWTO59193

Idea has been also raised for the adding it

https://www-secure.symantec.com/connect/ideas/rx4defssep-utility-sep121

Forum

https://www-secure.symantec.com/connect/forums/clear-defs-121

Can RxDefsSEP tool are woriking in sep 12.1.2?

RxDefsSEP utility not working in SEP 12.1 Environment ,In sep 12.x virus defination location are different location,You can create script for remove corrupt virus defination or manually clear out definitions.

Can't be used in 12.1

Follow these steps to clear out defs in 12.1

How to clear out definitions for a Symantec Endpoint Protection 12.1 client manually

http://www.symantec.com/docs/HOWTO59193