Project won't open

A .prj file fails to load — Composer reports a parse error, missing media, or refuses with no explanation.

Common causes:

• Composer version mismatch. A project saved on a newer Composer build can use components or attributes the current build doesn't know about. Update Composer to a build at least as new as the one that saved the file.
• File corruption. Unexpected hard shutdown during a save corrupts the XML. Composer keeps a .bak autosave file alongside the project — use it.
• Missing media. Composer searches for missing media in the Media/ folder around the project. If it can't find a referenced file, it'll either prompt or fail to open. Run Consolidate Media on the original host before moving the project.
• Encrypted project (.prjp) with the wrong key. The receiving host must hold the matching key. Without it the import fails; this is intentional. Get the matching key from whoever exported the project.
• Web Page Input on a Linux runtime. The Chromium-based Web Page Input runs on Windows only. A project that uses it will fail to open (or load with a missing component) on a Linux runtime host. Either run the project on Windows, or replace the Web Page Input with a pre-rendered video clip / an upstream RTMP feed of the same content.
• Default project name. If you saved your project as default.prj, a Composer update may have overwritten it. Restore from the day-stamped backup (YYYY-MM-DD_default.prj) in the Projects folder.