Ultimaker Cura always starts with an empty build plate in a new project environment. To start a new project after using Ultimaker Cura for a while, go to 'File > New Project...'.
Starting a new project has the following effects:
- All 3D models are cleared from the build plate
- All unsaved print profile changes are cleared to its original value
Tip: Use the shortcut keys 'CTRL/CMD + N' to quickly start a new project.