Cannot find active sheet: TypeError: read properties of undefined (reading 'source')

Question

I'm trying to add the current date to a cell in column K when any cell in that respective row is changed.

I found this script and altered it for my situation so I can deploy it as a trigger:

function onEdit(e) {
    var sh = e.source.getActiveSheet();
    if (sh.getName() !== 'pipeline' || e.range.columnStart == 1 || e.range.columnStart > 10 || e.range.rowStart < 6) return;
    sh.getRange(e.range.rowStart, 11).setValue(new Date())
}

As you can see I'm searching for tab named pipeline, which exists, it's the 3rd tab in my target sheet.
However, when I click the Google Apps Script Editor "Run" button I get:

TypeError: Cannot read properties of undefined (reading 'source')

Instead of editing the code, I also tried going to my target sheet pipeline and made some changes. When I then check the trigger itself I see that it's being executed but with errors:

I then inspect the errors (they're all the same) and see

TypeError: Cannot read properties of undefined (reading 'columnStart') at onEdit(Code:3:48)

I read multiple articles recommended by Rubén below, but none of them seems to address my issue (e.g. they address a mismatch in cell values, which I'm not checking for and using forms which I'm not using).

From what I can derive from the error, initially I thought the e parameter was not found, but sh.getName() check is passed, so e seems to be fine.

But I don't see why e.range.columnStart seems to fail. What am I doing wrong?

Answer 1

The trigger list shown in the question tells that there is an installable trigger that runs on every change to the spreadsheet. The event object of this type of trigger lacks the source and range fields the code attempts to reference.

The onEdit(e) function is a simple trigger that runs automatically when the spreadsheet is manually edited without installing any triggers separately. Its event object includes the necessary fields.

To avoid the issue you describe, simply delete the installable trigger you have created.