During deployment with MDT 2013, the following message is displayed: "Open File Security Warning Prompt". You have to click OK multiple times to get through the task sequence. Very annoying if you aks me! This because of the following problem: The issue is that when you download an .EXE, .ZIP, or .CAB Internet Explorer saves the Zone Identifier. This goes back to a feature that first appeared in Windows XP Service Pack 2 and Windows Server 2003 Service Pack 1 and the feature works the same in later operating systems.
In my case this on ithe following files: gfxtray.exe, hkcmd.exe, igfxpers.exe and rtdcpl64.exe. Just rightclick the .EXE, click properties, and then click the “Unblock” option. After that no "Open File Security Warning Prompt" popup appear anymore!
Just nice to know if you ask me ;)