Turn on "File name extensions" in your OS settings to ensure you aren't double-tagging the file.
Right-click the highlighted files and select Compress to ZIP file (Windows 11) or Send to > Compressed (zipped) folder (Windows 10). convert zip to sb3 fix
Go inside the extracted folder. You should see project.json . Turn on "File name extensions" in your OS
Scratch has a limit on individual asset sizes (usually 10MB per sound or image). If your ZIP contains massive 4K images or long high-bitrate MP3s, the conversion to SB3 will "work," but the file will fail to load in the online editor. the conversion to SB3 will "work