Copy-paste fix pattern
ClosedBit Runtime.exe app.cbaWhy it happens
ClosedBit Runtime was opened without an embedded app package and without a .cba path.
How to fix it
Open an exported .exe, double-click a .cba associated with Runtime, or pass the package path after ClosedBit Runtime.exe.
Runtime and Studio now show this kind of page from the error dialog: plain message first, stable code second, original details third.