Change the resulting Archive.zip to ProjectName.sb3 . Common "Convert ZIP to SB3" Fixes

How to Convert ZIP to SB3 (and Fix Common Errors) If you’ve ever tried to upload a Scratch project only to realize you have a .zip file instead of a .sb3 file, you’re not alone. Scratch 3.0 projects are essentially compressed archives, but the editor won't recognize them unless they have the correct extension and internal structure.

Here is a comprehensive guide on how to convert ZIP to SB3 and how to fix the most common errors that occur during the process. What is the Difference Between ZIP and SB3?

If your ZIP file doesn't contain a file named project.json , it isn't a Scratch project. You cannot simply turn a folder of random images and sounds into an .sb3 without the JSON file that tells Scratch how to use them. 2. Double Extensions

Your computer might warn you that changing extensions can make files unusable. Click Yes or Use .sb3 .

Technically, an .sb3 file a ZIP file. If you were to change the extension of any Scratch 3.0 project from .sb3 to .zip , you could open it to see the project's internal components: project.json: The code and logic. SVG/PNG files: The costumes and backdrops. WAV/MP3 files: The sounds.

Highlight everything inside that folder (Ctrl+A or Cmd+A). Do not select the parent folder itself.

Right-click the highlighted files and select Compress to ZIP file (Windows 11) or Send to > Compressed (zipped) folder (Windows 10).

Delete .zip at the end of the filename and type .sb3 .