What is happening?published at 10:37 British Summer Time 19 July
Problems first began to be reported in the early hours, with software giant Microsoft saying it was taking "mitigation actions" to deal with the outage.
It has led to major disruption for banks, shops and airports across the world - including East Midlands Airport.
A spokesperson said it was affecting the IT system used by ground handling agent Swissport to check in passengers and board them on to aircraft.
As a result, carriers TUI and Ryanair are having to check in passengers manually.
