You have just converted a Zip to an SB3. Double-click the file, and it should launch in the Scratch Offline Editor.
Windows: Right-click the highlighted files, select (Windows 11) or Send to > Compressed (zipped) folder (Windows 10). Mac: Right-click the highlighted files and choose Compress .
If you are using a Chromebook, tablet, or a locked-down school computer that prevents you from changing file extensions, online conversion tools are a great alternative. convert zip to sb3
: Scratch does not store assets by their human-readable names (like cat.png ). Instead, it renames them using an MD5 hash—a unique string of characters based on the file content (e.g., 83c25d51718e82d7ff1b192181cf26b6.svg ).
While converting ZIP to SB3 is generally a straightforward process, there are some limitations and potential issues to be aware of: You have just converted a Zip to an SB3
Replace .zip at the end of the file name with .sb3 .
Mac users can use the native Finder utility, but need to be careful with hidden system files. Open the folder containing your Scratch assets. Mac: Right-click the highlighted files and choose Compress
Get-ChildItem -Filter *.zip | Rename-Item -NewName $_.Name -replace '\.zip$','.sb3'
Hover over and select Compressed (zipped) folder . (On Windows 11, you can simply click Compress to ZIP file from the context menu).