I have been getting hugely frustrated with Powerpoint, often very simple key stroke commands (copy, paste, nudge, text etc etc) cause Mac's spinning beachball, often for up to 30 seconds at a time.

This seems to happen more at certain times of the day, particularly mid/late afternoon.

The strangest thing is that if I stick to using the mouse to navigate the menu and enter exactly the same commands without using the keyboard, no delays occur at all.

Any thoughts on the causes or how best to fix?

Thanks