notes attached to cells not visible, broken since last excel update (Office 365 on Mac)

dewege 

In my case it turned out that the Note textbox changed it's dimensions and reduced the height to pixel = 1. That's the reason why I saw only the arrows.

Here's what I did to fix it:

1. Right Click on the affected cell --> Show/Hide Note (to have the arrow visible on the screen)

2. Right Click on the affected cell --> Edit Note

3. Zoom in so you can see the very thin hairline that looks to be note textbox.

4. Click on it so the little resizing points appear on the screen.

5. Drag one of them down so the Note appears.

Hope this helps!