The striker said his 'dream comes to an end' after his loan from Chinese side Shanghain Shenhua expired.
Ighalo took to Instagram to show his appreciation to supporters after hism year-long spell at Old Trafford ended.
The striker said: "It's hard to see this dream come to an end. But I give God the glory for helping me fulfil this life long dream of putting on a Manchester United shirt as a player and represent this great club.
"It was indeed an honour I will forever cherish and be grateful for."
