Unable to select multiple artboards

I've looked up how to select multiple artboards at helpx.adobe.com and found the following:

1. Select the Artboard tool from the Tools panel.



2. Do one of the following:

· Press Control/ Command + A to select all the artboards in your document.

· Shift-click to select artboards.

· Shift-click the canvas and drag the cursor to select multiple artboards using a marquee.

None of the above works:

· When I press Control/Command + A, nothing happens.

· When I shift-click on boards, the first one I click on stays selected, nothing happens when I click on subsequent boards.

· When I shift-click the canvas and drag the cursor, instead of selecting boards, it creates a new artboard.

Is there a preference or something that is causing this to happen?

I'm using Adobe Creative Cloud 2017, the most recent update. OSX 10.10.5 (Yosemite)

Angela