The Dutchman was due to arrive at United's Carrington training ground to take up the reins only four days after guiding Holland to third place at the World Cup in Brazil.
Van Gaal opted against taking a holiday and will instead throw himself into United life, meeting those players who are not on a post World Cup break as well as club staff.
The 62-year-old, United's first manager from outside the British Isles, will have no time to ease himself in.
On Thursday he will be officially presented at a press conference before jetting off to the USA on Friday for the club's pre-season tour.
United will play matches against the Los Angeles Galaxy, Roma, Inter Milan and Real Madrid before beginning their Barclays Premier League campaign at home to Swansea on August 16.
Source : PA
Source: PA