After making system updates, background programmes may crash or get damaged. Most of the time, cleaning or forcing shutting background programmes, including the wayward Instagram app, will cure the problem. Here's how to do it:

• To open the app switcher, press the Home button twice fast. It will show you previews of the applications you've recently used but haven't closed.
• To dismiss the Instagram app preview, swipe up.
• Carry on with the remainder of the background programmes in the same way.