Proprietary music or DJ software files are project formats created by specific programs, like Ableton Live (.als), FL Studio (.flp), or Serato DJ (.history). These formats store unique project data including tracks, edits, effects settings, automation, and performance cues, tailored to how that particular software operates. They fundamentally differ from open, interchangeable audio file formats like WAV or MP3; you cannot open them directly in a different software application unless it was explicitly designed to support reading that specific proprietary format. Compatibility resides primarily within the software that created them or within the same product family.

To open these files, you typically require the original software used to create them. For instance, an Ableton Live Set (.als) requires Ableton Live software, while a Serato crate file needs the Serato DJ Pro application. Sometimes, files created in a newer version of the software won't open reliably in older versions. Within suites, like Native Instruments' Traktor, files might open across related applications (e.g., Traktor Pro and Traktor Scratch). Converting track lists to standard text formats like .m3u can sometimes bridge gaps between DJ platforms for simple playlist sharing.

While proprietary formats ensure full feature preservation and workflow integrity within their ecosystem, the main limitation is vendor lock-in, restricting access to projects without the specific software. This can cause issues with collaboration or long-term archiving if the software becomes obsolete. Ethically, some debate surrounds formats locking user-created projects to a single platform. Practically, users must ensure they retain the software or export stems/final mixes to open formats. Future trends involve cloud platforms potentially offering broader project compatibility.