Something along these lines,
On your Windows PC
- Select File then Export to Catalog
- Select a name and location for the new export catalog
- Wait a long time for it to copy the catalog file and all your photos to the new location.
On your Mac
- Create a new Catalog in your desired location
- From the File menu choose Import from Another catalog
- Chose to either
- Import files and leave them where they are
- Copy files to another location and then import
- Option a is quicker, but doesn’t move the files
Option B is slower, but will move the files to another location if thats what you want.