Hi,

   SEPM\data\inbox\log\traffic subfolder has many .err and .dat files. Hence, it has occupied a lot of hard disk space. What can be the possible cause and how to resolve? please suggest.

Stop the SEPM service, delete them, and then restart the SEPM service and monitor the folder to see if it builds up again.

Check this thread

https://www-secure.symantec.com/connect/forums/sepmdatainboxlog-many-err-files

Ok. However my concern is that deleting those files will not cause any problem.

These are the files which are sent from clients to the sepm server. You need to check your log retention policy, check the number of days its allowed to keep. Reducing it will eventually reduce the hard disk utilization.

Managing log data in the Symantec Endpoint Protection Manager (SEPM)

http://www.symantec.com/business/support/index?page=content&id=TECH90856

No,

When you have restart sepm services it's automatic created again.

Or you can use this tool

Using the "SymDelTmps" utility

 http://www.symantec.com/business/support/index?page=content&id=TECH105050

You can check this thread also

https://www-secure.symantec.com/connect/forums/sepmdatainboxlog-many-err-files

Agreed with above comments But make sure if you are working in production environment then take proper downtime and do the activity.

"Ok. However my concern is that deleting those files will not cause any problem." - these files are already .err - reoving them will cause no harm as SEPM won't process them anymore in this form.