Some more pessimistic supporters have already nicknamed the Dutchman "Erik ten months", because they doubt his ability as a coach.
David Moyes lasted 10 months before he was sacked after signing a six-year deal with Manchester United. The fear of most fans is that the club is the problem, rather than the manager. In the nine years since Sir Alex Ferguson retired, four different managers have come and gone.
The world of Man United is broken.
Judging by the fate of his predecessors, Ten Hag needs to do something quickly. It was clear during talks with United that it was unrealistic for them to expect a serious challenge in the premier league overnight, according to sources.
Ferguson failed to qualify for a full season in charge. It was impossible to finish in the top four after a damaging 2-0 defeat to Goodison Park in April of 2014. After winning the FA Cup in his second season, Van Gaal was sacked, despite finishing fifth in the league.
In his first season as United's coach, he finished sixth, but made it to the playoffs thanks to winning the Europa League. He was fired in December of last year after his team fell behind in the race for the top four. Solskjaer finished third and second in his two full seasons, but was fired before Christmas in his third year because of the lack of interest in the playoffs.
Although he said in his first official news conference on Monday that he was here to end their era of dominance, Ten Hag might not be under immediate pressure to leapfrog Manchester City andLiverpool in the premier league. It will not be easy.
Those closest to Ten Hag think he has the skills and work ethic to be a success. He made a point of introducing himself to each reporter while speaking on Monday. He said that he wanted to bring back success and play entertaining football, but he also made it clear that he was single-minded.
He has spoken to a lot of people about the job he is taking on, but his final sentence of his news conference was that he will do things his own way.
If the club continues to make bad decisions off the field, he will be the next fall guy. The mess behind the scenes was one of the things that made the second-place finish with United one of the greatest achievements of the man.
The man who spent time at United and played under Ten Hag said that he was quite confident in him at Manchester United, but he needed the board behind him.
Arnold, who replaced Ed Woodward as chief executive in February, has promised to be more hands off when it comes to football decisions but most things are still going to owners.
The coach of Manchester United wants to include the player in his plans.
Even though he has been a success at Ajax, Ten Hag is still yet to manage a game in any of Europe's top five leagues and that is a risk for United, but also a risk for him.
Since being demoted to the second tier of English football in 1974, he is arriving at one of the lowest ebbs. There is a lot of ground to make up to get back into the top four after recording their lowest points total in the history of the league. A number of players are set to leave the club in June, including Jesse Lingard and Juan Mata, as well as Anthony Martial and Eric Bailly.
The dressing room atmosphere during the second half of the season was said to betoxic, with players forming and distrusting each other. According to sources, part of the reason for appointing former Ferguson assistant Steve McClaren as a coach is to improve the mood and togetherness within the squad.
According to sources, all eyes will be on how Ten Hag handles the captaincy, with the squad split over whether Harry Maguire should continue with the armband. If there is a change, there are three candidates to take over, including David De Gea, Bruno Fernandes and CR7.
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According to sources, Ten Hag is not going to start under the new boss because of his lack of pace and the fact that he plays with a high defensive line. There are doubts about De Gea's ability to play in his system, although there is an acceptance that signing a forward and a center back is more important this summer than changing between the posts.
The club hasn't laid on the easiest summer schedule after a three-week tour of Thailand and Australia, but Ten Hag wants to get the players back for preseason training as early as possible as he begins to work through the issues.
Ten Hag wants to wake a sleeping giant. United fans have seen enough misery since Ferguson retired to know that any optimism should be cautious. Most United supporters will only believe in success when they see it.