We have recently identified an issue where Flowcode unexpectedly closes under the following circumstances:
The current project is reloaded
A project is open and a new project is created
A project is open and another project is loaded
This has been fixed and an update will be available within the next few weeks.
Until then there is a workaround to avoid this issue. If you have project open, then please explicitly close it (via file...close) before creating or opening another Flowcode project.