's dismal season whimpered to a disappointing end after a woeful run of results was capped off by a shock defeat by already-relegated Cardiff City.
Ole Gunnar Solskjaer's sensational start to life as Old Trafford boss was rewarded with a permanent post – but results, and the atmosphere, soon turned sour.
It is the most important summer of the Norwegian's career and he must get United off to a flying start next season. Here, Sportsmail's
MIKE KEEGAN highlights what needs to be done.
It is understood that Solskjaer was staggered by the lack of fitness among the ranks when form started tailing off following his explosive start to life in the dugout.
Carrington insiders say that the sports science department was virtually redundant under predecessor Jose Mourinho, who used more traditional methods.
While many of the fitness and conditioning staff will be re-engaged, Solskjaer is currently considering whether to make further additions.
Towards the end of the season there was a feeling that United's well-paid players simply could not perform as they should due to a lack of fitness required at the elite level.
Unforgivable. Solskjaer has already made sorting it a priority.
Clear the deadwood
There are two schools of thought here. Some believe that under the right system and manager, United's underperformers can flourish and that it would be a mistake to jettison those who may go on to be successful elsewhere.
There can, however, be no denying that there needs to be a substantial clearance sale. The bizarre thing is, some of those who should be out of the door were given contract extensions close to the end of Mourinho's reign.
Elsewhere, if Solskjaer can get a tune out of Alexis Sanchez he should be up for a Grammy Award. Finding a taker for the £500,000-a-week misfit may be an even more difficult task. Few would shed any tears if half the squad were punted out of the door.
Sort Martial's attitude
It may not be too late for Anthony Martial to avoid becoming the £50m down the drain United's fans used to joke about in one of their chants.
Martial has not impressed Solskjaer with his attitude and (like many others) fitness levels. This is a player with incredible natural talent who can make a real difference.
If Solskjaer can sort mind and body he may be well rewarded in the forthcoming season.
There are few players who have the desire for United to succeed as much as the local lad, who has looked a different player when on duty with England.
Marcus Rashford is another who appears to have been struggling with various niggles. He is still only 21 and has perhaps been overused in recent times.
Rashford has explosive pace, can time his runs and has displayed that he can finish. All he needs is health, consistency and confidence.
Revamp the defence
This is the area that needs work more than any other. First, Solskjaer needs to sort out what is going on with David de Gea. If he signs a new contract – great.
If he doesn't - take the money and move on. Perhaps spend it on a pair of new full-backs. While he has not had the best of seasons in Scotland, with injury taking its toll, Celtic's Kieran Tierney would fit the bill of hungry, young talent.
It would appear that Eric Bailly and Victor Lindelof are the best centre-half pairing. That needs to be strengthened because it is simply not good enough to challenge.
Phil Jones cannot shake his injury nightmare and Chris Smalling remains inconsistent.
Find a new captain and leader
Or – build your team around Paul Pogba. Those close to the Frenchman reject any suggestions he is to blame for United's malaise, pointing out that he cannot be held responsible for the lack of quality elsewhere on the field.
Pogba is a leader and a talented player but he needs support and he needs to take extra responsibility.
Other candidates are few and far between and going out and buying a ready-made leader to come in and captain the side would be near impossible.