convert ZIP to SB3

The quick way to is simply to rename the file extension from .zip to .sb3 . This works because an SB3 file is essentially a renamed ZIP archive containing a project.json file and all associated media assets.

When a browser or file extractor saves a project incorrectly—or when developers share raw assets—the file is saved as a standard .zip , stripping away the Scratch signature. The result? Scratch says: "File failed to load."

Why Convert ZIP to SB3?

  1. Unzip the file: First, you'll need to extract the contents of the zip file. You can do this using a file extraction tool like WinRAR or 7-Zip. If you're using a Mac, you can simply double-click the zip file to extract its contents.
  2. Locate the Sb file: Inside the extracted folder, look for a file with the .sb or .sb2 extension. This is likely the Scratch project file.
  3. Rename the file: Rename the .sb or .sb2 file to have an .sb3 extension. For example, if the file is named project.sb, rename it to project.sb3.
  4. Import into Scratch: Open Scratch and click on "File" > "Load Project" (or press Ctrl+L on Windows or Cmd+L on Mac). Navigate to the location where you saved the renamed Sb3 file and select it.

: Ensure "File name extensions" is enabled in your system settings (View tab in File Explorer on Windows) so you can see and edit the extension. Confirm the change