Yes, you absolutely can edit Scratch 3.0 project JSON files—your issue isn’t about editing itself, it’s about how you repackaged the project into the .sb3 format. Here’s why you’re seeing that crash and how to fix it:

Common Causes of the Crash #

The most frequent reason for this error is an incorrect zip structure when you recreate the .sb3 file. Scratch expects the contents of the project to be directly at the root of the zip archive, not nested inside a folder. Even if you didn’t modify the JSON, zipping the parent folder instead of the individual files will break the project loading.

Other potential issues include:

• Using a non-ZIP compression format (like RAR or 7z)
• Using an incompatible compression method (stick to standard deflate or no compression)
• Accidentally renaming files (e.g., Project.json instead of project.json—Scratch is case-sensitive in some environments)

Step-by-Step Fix to Repackage the Project Correctly #

1. Navigate to the folder where you extracted the .sb3 contents—you should see project.json, plus folders like costumes and sounds directly here.
2. Select all the individual files and folders in this directory (do NOT select the parent folder containing them).
3. Zip these selected items directly:
   • On Windows: Right-click → Send to → Compressed (zipped) folder
   • On macOS: Right-click → Compress [number] items
4. Rename the resulting zip file to have a .sb3 extension (ensure file extensions are visible so you don’t end up with .sb3.zip).

Tips for Safe JSON Editing #

If you do plan to edit the project.json file later:

• Use a JSON-aware editor (like VS Code with the JSON extension) to avoid syntax errors.
• Validate your changes with a JSON validator before repacking—even a missing comma or mismatched quote will cause Scratch to crash.
• Keep a backup of the original .sb3 file in case something goes wrong.

Following these steps should let you upload your project without the crash.

内容的提问来源于stack exchange，提问作者Anas M K