It is best to keep copies of your info using the "Backup Collection" feature. In the case where you only have the track2.mfd file, you might be able to use it but it can be tricky. The file could be input manually into the correct directory on the PC, but handling the file manually can cause a permission issue; especially if you move it from one computer to another. If you want to try it; close MaxSea and go to "\Programdata\MaxSeaInt\Data" and make a backup copy of your existing track2.mfd file. Then take your old track file and overwrite the normal/current one and then try opening MaxSea and see if it works for you. If it doesn't, restore your original copy and write it up as a lesson learned to conduct regular backups.