Before doing anything crazy like reformatting your computer, I say this jokingly but there have been many who went nuclear for things that had a simpler fix, here are a few things to try, and hopefully, you’ll restore the printing function from your Mac to your DYMO.
“Out of Labels” Error
Make sure you load the media roll properly.
…and if all else fails…
Uninstall and reinstall the correct drivers for your DYMO. InventoryLab created an awesome procedure to follow: https://goo.gl/6Sr5ES