Andy, that don't sound right. While 2011 is a long time ago, BIAB has always made claim of full backword compatibility with this stuff. I have files that go back well beyond 2011 and will test your hypothesis. In the mean time you did use the RTF setting button, right?
Hi Dan, I did return to factory settings, but this didn't seem to make any difference. The rendering process still hung, and I had to use Task Manager to close the program (this was after leaving the machine well alone for 45 minutes).
On a lighter note, I managed to write and render 8 files in just over an hour, including finding the correct changes on PDF first, so all in all a success!
I would be interested to know if you have any further theories though, as time spent retyping can always be used more profitably elsewhere!