Slitherine

New game, both with 2.1, one PC, one Mac. PC first move won't open on Mac - get message "Exception - game loaded in a previous version and won't load" Help?

Well
Have you played this player before?
This message points to the fact that the game file was not started with v2.10 or the game started is not the final version from Slitherine. (ie a previous beta version)

Another idea is the correct file being sent? You have to make sure you are going to the correct path and selecting the correct file.

I always suggest to name the file with the players initials, what number game, and version so you send the correct file to the right player if you have several games going.