A few minutes after starting my computer (Windows 7 Pro desktop) and Avast updated itself, Avast threw up the “threat detected” warning and pointed to http://files.avast.com/files/emupdate/20131217.exe, which seems to be its current update file. It said it was infected with Win32:Downloader-TJK [Trj]. I’m assuming this is a false positive, but I want to be sure. I am currently running a full scan, but wanted to post in case anyone else has run into this issue.
it helps searching forum before posting 
http://forum.avast.com/index.php?topic=142970.0
Hi, I did search on the name of the trojan and the name of the target file before I posted. Nothing came up, and there were only a few minutes difference between the posts. So thanks for the link. 
Same happened to me few mins ago. I was like :o
Same happened to me on a client’s computer about 7 hours ago. I don’t see any answers here or in the links posted. It is the same Trojan in the title of this thread.
was it also the same file/url detected?
http://forum.avast.com/index.php?topic=142972.msg1036823#msg1036823