High Disk Space is being consumed by C:\Program Files\Symantec\Symantec Endpoint Protection Manager\data\outbox\Importpackage

. Delete all files from %installlocation%\Symantec\Symantec Endpoint Protection Manager\data\outbox\ImportPackage folder. (without stopping any services)
2. Delete everything older than today's date in %installlocation%\Symantec\Symantec Endpoint Protection Manager\Inetpub\content (also without stopping any services)
3. In the Symantec Admin Console go to Admin > Servers > localhost. Right-click localhost and truncate the transaction logs.


Symantec has released new version of Symantec Endpoint Protection. English versions of Symantec Endpoint Protection 12.1.5337.5000 (RU5) is now available.
It has new content storage optimization feature:
As part of the upgrade to SEPM 12.1 RU5, the SEPM converts all of the content from full definitions to delta definitions. This process is resource intensive and may take an extended period of time. After this process is completed, the SEPM will use significantly less disk space.
In a typical enterprise setup where 30 content revisions stored, the SEPM upgrade process must reduce 55GB of full content to under 2GB of delta content. This process requires significant resources to complete and is impacted by the performance of any available CPUs, CPU cores (physical/logical/hyperthreading), memory, and disks (I/O). On a server that performs multiple roles, stores larger numbers of content, or is otherwise resource constrained, this process may take a longer duration to complete.
Refer this article to find more info: The LiveUpdate content optimization and content storage space optimization steps take a long time to complete when upgrading to Symantec Endpoint Protection Manager 12.1 RU5
http://www.symantec.com/docs/TECH224055