An is the file extension used by Scratch 3.0. It stores everything in your project—scripts, backdrops, sprites, and sounds.
If you change the extension to .sb3 and attempt to load the project into Scratch, you might encounter an error message stating or "Project failed to load." Here is how to fix the most common culprits behind a broken conversion. Fix 1: Correct the Internal Folder Structure convert zip to sb3 fix
Select all items inside the folder ( project.json and all asset files). An is the file extension used by Scratch 3
If you receive a "Failed to upload" error when loading your new Fix 1: Correct the Internal Folder Structure Select
Right-click the selected items and choose (Windows) or Compress (Mac). Rename this new ZIP archive to end in .sb3 . Fix 2: Repair a Missing project.json File
file are in the root of the ZIP folder, not inside a sub-folder. Compress the Files