I have been using Music Maker 2014 and it developed a fault and had to close. I had been working on a file all day and saved it several times however it now tells me it can't open it. Is there any way to retrieve this arrangement?
First reset the program to its defaults to ensure there is not a problem waiting to appear again - File, Settings, Reset program to defaults - note you will lose any customised settings you have made.
MEP will have created backup files of the projects - the should be in the projects folder and have a .mv_ file extension and can be loaded from File, Load backup project.
There may be several version so work backwards from latest until you find one that loads corectly and then save the project.