I have been having this problem with VW12 for a couple of months. I have tried everything suggested by several people at Tech support. I have uninstalled and reinstalled Quicktime and Vectorworks in every possible configuration and sequence. Nothing works for more than a couple of days. No one at VW is calling me back or returning emails. I need to know if my files can be reformatted so I can go back to VW10. I presume that no progress has been made on solving this problem and I can't work productively if I have to reinstall the software several times a week.
