Archive.png This article or section documents something not included in the current version of Scratch (3.0). It is only useful from a historical perspective.

There was a system in Scratch 1.4 that detects scripting errors or other problems.

If, while running a project, The Scratch Program finds a mistake, it will attain a red border around the script and stop the program from running any further. The block (or blocks) causing the problem will turn red.


Errors can be caused by the following:

  • Dividing by zero
  • Using an invalid input in function block (operators)
  • Using a motion block in the Stage
  • Attempting to access the nth item of a list where n<0

Turning off Error Catching

To turn the Error Catching off, click the R in the Scratch logo while holding shift and click the "turn error catching off" option. If error catching is off, then Squeak will show an error dialog when an error occurs that shows where the error occurred and offers debug options. This is generally not useful in Scratch projects but can be used help debug added features in modifications.