There are a number of different variables that could be causing the issue. Is the older version you are coming from a Mac App Store version or a Mariner version? Did you purchase MacGourmet Deluxe 4 in the Mac App Store or through Mariner? Let's run through a few common scenarios:

-MacGourmet or MacGourmet Deluxe 3 Mariner version upgrading to MacGourmet Deluxe 4 Mariner version

Locate your old MacGourmet or MacGourmet Deluxe database by going to the Help menu in the menu bar and select "Where is my Database". This will locate the MacGourmet database on your Mac.  If you are using a very old version and don't see that feature in the Help menu, you'll need to manually search your Mac for the database file. The file name to search for should be something similar to "macgourmetdatabase" and usually can be found in your Documents folder. Once you have found the database make sure you relocate to your Documents folder. If it's already there, make sure it's the ONLY MacGourmet database in your Doucments folder. Relocate any others you might have to your desktop for now. At this point, open MacGourmet Deluxe 4 (it is assumed that you have upgraded to MacGourmet Deluxe 4 and have installed it on your Mac) and your recipies should automatically import. You may need to register MacGourmet Deluxe 4 with your new serial number (by default, all Mariner apps are full functioning trial copies which turn into non-expiring copies when registered with a serial number). 

-MacGourmet or MacGourmet Deluxe 1 or 2 Mariner version upgrading to MacGourmet Deluxe 4 Mariner version

Locate your old MacGourmet or MacGourmet Deluxe database by going to the Help menu in the menu bar and select "Where is my Database". This will locate the MacGourmet database on your Mac.  If you are using a very old version and don't see that feature in the Help menu, you'll need to manually search your Mac for the database file. The file name to search for should be something similar to "macgourmetdatabase" and usually can be found in your Documents folder. Once you have found the database make sure you relocate to your Documents folder. If it's already there, make sure it's the ONLY MacGourmet database in your Doucments folder. Relocate any others you might have to your desktop for now. At this point, download a trial cop[y  of MacGourmet Deluxe 3 from our web site here...

https://s3.amazonaws.com/MarinerDownloads/index.html

and install it on your Mac. Just keep it in trial mode, you don't need to purchase it. Open MacGourmet Deluxe 3 and your recipes from your older version should automatically import into MacGourmet Deluxe 3. Quit out of MacGourmet Deluxe 3 and open MacGourmet Deluxe 4 (it is assumed that you have upgraded to MacGourmet Deluxe 4 and have installed it on your Mac) and your recipies should automatically import. You may need to register MacGourmet Deluxe 4 with your new serial number (by default, all Mariner apps are full functioning trial copies which turn into non-expiring copies when registered with a serial number). 

If all else fails, contact us at support@marinersoftware.com and we'll help you.