Systems may open two copies of a file when multiple processes or users attempt to access the same file concurrently without proper file locking or synchronization. This differs from accessing a read-only copy where changes aren't saved back to the original. When one application writes changes while another simultaneously edits a different copy, the later-saved version usually overwrites the earlier changes, potentially causing data loss.

A common example occurs when opening the same document file (like a spreadsheet) simultaneously on both a local computer and a cloud-synced drive service, creating separate editing sessions. Collaboration platforms like shared network drives in enterprise environments might also temporarily create local copies if multiple users open a file without co-authoring features enabled, particularly with simple text editors or legacy software.

The advantage is potential isolated editing convenience. However, significant drawbacks exist, primarily the high risk of conflicting versions and lost work if changes aren't correctly merged. This behavior creates data integrity issues and user frustration. Future developments focus on improved cross-platform synchronization protocols and more prominent user warnings to prevent inadvertent file duplication and promote safer collaborative editing practices.