[DataFile] Data file ‘C:\Users\sbagl\Downloads\Contacts List.emdf’ failed to open.
Error message, then it crashes.
That could possibly mean your .emdf file has possibly eg: been moved since it was created.
If it hasn’t been moved and you can see it ok in your downloads folder and “rebooting your computer makes no difference”, then if you have a current active paid Pro or Personal version, reccomend you go to the VIP support page and login and lodge a support ticket for assistance.
I uninstall the Emclient program completely and then reinstalled it, and that seemed to fix the problem.