When Adobe Reader or Acrobat is deployed in the enterprise with enhanced security turned on, warnings can appear in the client. The warnings appear when Acrobat tries to merge data into a PDF. These warnings are confusing to the users and you may want to suppress them by defining the source of the data as trusted.
Define the sites that host the PDF and data files as trusted. You can do this by adding the site where the data is stored to the Windows trusted sites list (Windows > Control Panel > Internet Settings > Security), or to the enhanced security settings in Acrobat/Reader (Edit> Preferences > Enhanced Security).
The Windows trusted sites list is saved under the following registry key:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Zone Map\Domains
You can therefore add the sites directly under this registry key if you are using an automated deployment of Acrobat/Reader.