Symptom:
The AVG or NOD32 or GDATA add-in deletes the message body.
Solution:
To remove an add-in:
Outlook 2007: Tools > Trust Center > Add-ins
Outlook 2010/2013/2016: File > Options > Add-ins
In the Manage field choose COM add-ins and click Go
Highlight an add-in and click Remove
Source:
intermedia.net