If the project still fails to load in Scratch after following the steps above, the archive or the code may be corrupted.
(Insert into existing project.json’s top-level object if missing.)
# Example Python fix for SB3 corruption import zipfile, os def fix_sb3(corrupt_file): with zipfile.ZipFile(corrupt_file, 'r') as z: z.extractall("temp_fix") with zipfile.ZipFile("fixed.sb3", 'w') as z: for file in os.listdir("temp_fix"): z.write(os.path.join("temp_fix", file), file) print("Fixed SB3 created.")
I can provide tailored steps to get your project working again. Share public link convert zip to sb3 fix
Is there a text version tool can convert text to scratch blocks? #7660 11 Apr 2025 —
Sometimes, high-level compression methods (like Ultra or 7z-specific formats) confuse the Scratch parser.
Before diving into the conversion process, it helps to understand what these files actually are. If the project still fails to load in
This paper outlines the technical relationship between archives and Scratch 3.0 (
If you have a .zip archive that contains your Scratch project data, you can manually convert it back to an .sb3 file using just your operating system's file tools. Here's the process:
Back to the hex editor. He compared his project.sb3 to a known good file from an older project. At the very top, the first 18 bytes of the good file read PK\x03\x04\x14\x00\x00\x00\x08\x00... – the standard ZIP local file header. But his file started with a different pattern, the ghost of the outer ZIP layer. #7660 11 Apr 2025 — Sometimes, high-level compression
The loading spinner spun. One second. Two seconds. Five.
Turn on "File name extensions" in your OS settings to ensure you aren't double-tagging the file.
Right-click (or Control-click) the file and select . Under the Name & Extension tab, delete zip and type sb3 . Press Return .
Select the items inside this folder (Ctrl+A on Windows, Cmd+A on Mac). Do not select the parent folder itself. Right-click the highlighted files:
Copy the entire text and paste it into a free online tool like .