Select Compress to ZIP file (or Send to > Compressed (zipped) folder ). Mac: Select Compress X Items . A new .zip file will appear.
If your ZIP file already contains the correct internal file structure (meaning the project.json file is sitting directly in the root directory of the ZIP archive), you do not need any special software. You can simply rename the extension. On Windows:
There are several scenarios where converting a ZIP file to an SB3 file becomes necessary: convert zip to sb3 updated
Are you getting a when trying to open the file?
Are you getting any specific when opening it? Share public link Select Compress to ZIP file (or Send to
To test your file, open the Scratch MIT Editor, click , select Load from your computer , and choose your new .sb3 file. To help tailor this guide further, let me know: What operating system are you currently using? Did you manually edit the project.json file inside the ZIP?
If Scratch doesn’t load the file, ensure project.json is at the root of the ZIP (not inside an extra folder layer). If your ZIP file already contains the correct
If the ZIP contains a folder with project.json and asset files, you need to package that folder as a ZIP archive first, then rename that ZIP to .sb3 . Alternatively, use the manual renaming method to convert the ZIP directly to SB3 — it will work if the contents are structured correctly.