Quicken Unknown Error is a small issue. You can wait 24-48 hours, and the application will automatically fix the issue. However, if you still face the issue after the given time frame, we recommend you follow the steps below. By following the methods given here, you will be able to fix the Quicken 2016 An Unknown Error Has Occurred issue. Before starting the troubleshooting steps, you need to analyze the reasons behind this issue.