Many thanks, will try to use shrink instead
As killjoy and I noted, it has nothing to do with your use of CloneDVD2. It has to do with the target value for the shrunken disc. I do recall that some movies (when I was still compressing them - use DL discs now) with DVD shrink would not get under 4.37 GB on the first try, and you had to shrink the output a second time. If you didn't change the default target size in CloneDVD2, perhaps that is what is happening to you.
I am not convinced there is something else going on with this movie file im trying to back up, its fairly new and just tried shrink with it, get an error straight away, but CloneDVD2 works fine?!! weird