Exit from tag value change script

With Ignition 8.0.12

In a tag value change script:
import sys

if initialChange == 1:
if currentValue.value == 0:

Produce that error in the logger:

Any ideas?

sys.exit() is documented to kill the entire application. Obviously, Ignition doesn’t allow that. That it worked to exit certain kinds of event scripts was always a fluke. Don’t use it. Use return. If you aren’t in function context, delegate to a script module function where return will work.