Hi there, JanEG.
To fix the application error, you can uninstall your QuickBooks 2016 for Mac. If you need help on how to uninstall, please ask your I.T person for the steps.
Once done, you can re-install the application by following the steps in this article: Install and set up QuickBooks Mac Desktop.
Please let me know if you have any additional questions. I'll be around to help you some more. Thanks.
