If your project fails with an asset-related error, you can manually add the missing assetId property. Extract your .sb3 file, find the project.json , locate the problematic costume section, and add a valid assetId property. The assetId is typically the same as the md5ext value without the file extension. For example, if a costume has "md5ext": "3c6241985b581284ec191f9d1deffde8.svg" , its assetId would be "3c6241985b581284ec191f9d1deffde8" .
Note: If you don't see extensions, enable "File name extensions" in your file explorer settings.
: A developer-focused tool for programmatically converting and editing Scratch project files. convert zip to sb3 fix
Find the project.zip file on your computer. Rename: Right-click the file and select Rename .
If the .zip file is corrupted, you need to extract the contents and re-compress them. If your project fails with an asset-related error,
is at the root level of the compression, users can reliably modify and restore Scratch 3.0 projects without loss of data. or provide more details on automated repair tools sb3fix - fix corrupted Scratch projects - TurboWarp
For developers or advanced users who need to perform this operation programmatically or in bulk, command-line and API tools are invaluable. Find the project
Did you this ZIP file, or did an existing project file suddenly break?
If the project was just mislabeled as a .zip , this method is the fastest. Find the .zip file on your computer. Rename File: Right-click the file and select "Rename." Change Extension: Change the ending from .zip to .sb3 .
: Ensure all assets and the project.json are at the root level of the folder. Do not place them inside a subfolder within the ZIP.