Hi, I'm using MMM17 premium version and I exported an arrangement as an mp3 and have since lost the mmm file. When I import the mp3 into the arranger I get a message saying 'reactivation is possible in the settings dialogue' which I assume means I am able to return the file to the original format but I can't work out how to do it!

Question is did you activate the Mp3. I use MMM 16 Premium and here is a screen shot. If you have successfully exported Mp3 please note what you have done in your project file(mmm) is saved in audio file(Mp3) that can not be edit as what you can do in your project file(mmm). What do you mean by original format?

But if you use File Manager browse folder locate your Mp3 drag and drop on arranger then you can do some further editing of Mp3. Refer screen shot where file manager is?

The piece was 16 minutes long and I want to change it. Anyone's help greatly appreciated in advance. Thanks.

Use file manager then drag and drop Mp3 on the arranger and change. You can add some effects, make it shorter, or can copy and paste same item etc.

To open project file refer screen shot.

Note: if you have lost project file there is still one possibility to try your luck. When Music Maker is opened Click on File/then Load arrangements a window will be appeared click the drop down menu and change it to All files as per screen shot. You might got Backup file. Music Maker save Backup file in case something went wrong we can open it instead of projects file. Try to locate file with the name of your Mp3 file with the extension of BAK. If you find open it as you  open project file(mmm) you will have all of you saved work. Please save the project now you got your project saved and you can work on it.

I hope this answer will help you.

nihon94