Same problem for me when updating dota 2. Avast moved vtex.exe to chest (false positive) . Finally I ended up updating dota for 1.6gb instead of 109mb - after disabling avast.
Hope they give an update and make sure vtex.exe is not detected as virus. Similar problem in frozenThrone.exe for warcraft 3 frozen throne- being moved to chest. May be a bad virus database update, those who dint update would not have faced these issues.