I'm going through and answering all of these questions related to this issue, because when it happened to me I realized there was no one (that I could find) who knew what they were talking about.
If you have firewire attached to a computer and shut off the computer while still recording, or have the recording program running, this can happen. Another time it happens, is if you have firewire connected and cut the power to the board. (both of these instances happened on accident with me).
What it appears to do is spike the noise gate on channels 5-16 to their max. If you select those channels and click on "Gate" you'll see red bars sustained at their max level. I have tried to override this issue in a number of ways: under "System" in the noise gate settings; by changing the Firewire Link ID (the "firewire trick"); by doing a full factory reset, uninstalling and reinstalling all the drivers on my computer. None of this worked. The ONLY thing I have found that works, is to do a full factory reset and then just let it sit for a couple of days.
This seems to be a major flaw in the software of the 16.4.2, and possibly others around the same time. I can't believe they didn't make a fix for this, because I see it all over the internet.
