Thanks Mike.
I didn't want to muddy the waters with this one.
I don't know if this is significant or not, but when I installed 212 a Floating Point error or something similar was present for the first couple of times I opened QIU. That error has since vanished.
Also today when trying to sort out my thoughts with the matt problem, the program froze twice. Something I've not experienced before.
John
That could be anything. Could be a corrupted image header or corrupted QU settings. First try v2013.213 which I just released. That fixes the mat adding problem. Then we'll go from there but if you see any of the above again, I'll need a sequence to track it down such as what type of image(s) you are working with, exactly when the error appears, if the problem only occurs on some images (or folders), etc.
Mike