I use ver.8.5a and Windows XP. A couple of days ago I attempted to open a family file that contains some 40,000 people. The process of verifying posed bo problem, but about 20% of the way through compiling the Index of names, the procedure hung. Despite many more attempts, the problem persists. I had updated my backup on a USB drive the last time I had entered additional data, so the same problem arose when I tried to open this. I have other family tree files and had no difficulty at all in opening these. This suggests to me that the problem is not with the program, but perhaps with corrupt data. I would not be surprised if a number of other users have also had difficulties with this issue. If there is anyone out there who has had this happen to them and were able to resolve the matter, I would very much appreciate a response indicating how it was overcome.