Hello there, Motorworks.

You'll want to uninstall the old version and sure that you saved the company file with Verify and Rebuild Data Utility done. Then, you can fully install your new licensed QuickBooks Desktop for Mac. 

Here's how to verify and rebuild data:

1. Go to the File menu and select Utilities.
2. Click Verify Data, then select OK to close all windows. If you see “Your data has failed the integrity check” you need to rebuild your file. If there are no problems with your data, you’re done.
3. Select File, then select Utilities > Rebuild Data, then select OK to close all windows.
4. QuickBooks will ask to make a backup before rebuilding your company file, select OK.
5. If you haven’t set up any backup preferences, QuickBooks will ask you to update them. Select Backup Preferences and edit as needed, then select OK.
6. When the backup's finished, select Show in Finder to locate the backup or select OK if you’re done.
7. Once the rebuild's finished, select OK.

For the detailed steps you can use these references:

• Install and set up QuickBooks Desktop for Mac
• Verify and rebuild data in QuickBooks Desktop for Mac
• Back up your QuickBooks Desktop for Mac company file

I'm just here if there's anything else that you need help with. You take care!