I have the portable viewer on my work laptop (Win10 Pro) with Windows Defender. Today, all of a sudden, I couldn't launch the Viewer as it would close and disappear from my System Tray after double-clicking on it. On a hunch, I checked Windows Defender, and sure enough there was a new detection, of the following virus: Trojan: Win32/Rundas!plockhttps://www.microsoft.com/security/portal/threat/encyclopedia/entry.aspx?name=Trojan%3aWin32%2fRundas!plock&threatid=2147711527&enterprise=1
So now I'm unable to launch my Viewer, as the process gets killed right away. And for some reason, I'm unable to make an exception for it in Windows Defender, which may be a Group Policy in my corporate Windows 10.
This trojan has been around most of 2016, and most people claim it's a false positive, but being unable to add an exception for the Viewer exe in Defender, I'm stuck with no remote access.