Hello N350AZ,
We can find the most recent back up company file if you have the Intuit Data Protect. Please review the steps found in this article: Set up and Restore Intuit Data Protect (IDP) Backup Files.
If you're not using the IDP, you can try to check the most recent modified backup file stored. To locate it, please click on QuickBooks, select Preferences, and click on Backup.
You can also try Mac OS X Console to see the activities on your computer. This will help you identify where and when you save the recent QuickBooks company file. Please try searching on the web on how to use Mac OS X Console.
Let us know if you have any questions. Thanks!