Symantec Add-in Protection Slows down the Outlook 2010/2013

I have noticed that when Symantec Add-in is enabled in Outlook 2007/2010/2013, Outlook shows "not responding". There is some delay on scanning email.

Workaround, I disabled the Symantec Add-in:

You can enable/disable Outlook add-ins in the following locations;

• Outlook 2003 and previous
  Tools-> Options-> tab Other-> button Advanced E-mail Options…-> button Add-In Manager…/COM Add-ins…
• Outlook 2007
  Tools-> Trust Center…-> section Add-Ins
• Outlook 2010
  File-> Options-> section Add-Ins

Or 

Remove Email Scanner options from the Control Panel --> Programs and Features --> right click Symantec --> Change --> uncheck Email Sanner to disable the add-in.