Why are there several versions of Mr. Arkadin?

The existence of multiple versions of Mr. Arkadin (1955), also known as Confidential Report, stems from the film's troubled production history. Although the movie was based on an original story by Orson Welles, European investors removed him from the project during the editing phase.1

Because of this interference, the film circulated in at least three different versions during Welles’s lifetime, each containing slightly different material. It was not until 2006 that a "comprehensive version" was finally assembled to reconcile these discrepancies.1