We understand Moyes accepts his sacking on Tuesday was down to poor results which saw last season's champions slump to seventh - out of the Champions League and guaranteed their worst Premier League points total.
But in the months before his departure the Scot repeatedly suggested a major rebuilding job was required at Old Trafford this summer.
We understand Moyes felt some of United's players found it difficult to adapt to his methods following the end of the Sir Alex Ferguson era.
Our source also tells us Moyes did not manage to match Ferguson's father-son relationships with some of his squad.
Ferguson's successor was happy with what he saw on the training ground but felt his players often struggled to take their performances into matches.
And as for his dealings in the transfer market, we are told that United targeted many players the public did not hear about but struggled to attract top talent.
United's public pursuit of Cesc Fabregas ended in failure, while moves for Athletic Bilbao's Ander Herrera and Everton left-back Leighton Baines came to nothing.
The task of spending a reported £150m transfer fund this summer will now fall to Moyes' successor, and current Holland boss Louis van Gaal is the favourite for the job.
The former Barcelona manager's credentials were yesterday endorsed by Sky Sports' Spanish football expert Guillem Balague, who said: "He suits Manchester United down to the ground. The timing is perfect."
Next in the betting is Real Madrid manager Carlo Ancelotti, who had Ray Wilkins as an assistant during his time at Chelsea.
Wilkins told Sky Sports: "The name that jumps out at me is Carlo Ancelotti.
"The Copa del Rey is not enough for Real Madrid, so if he doesn't win La Liga or the Champions League, he may become available. He speaks English, knows the Premier League and I think he would be ideal."
In the meantime Ryan Giggs will lead United, beginning with this weekend's home game against Norwich.
It is believed Giggs will not be considered as a full-time replacement, but they hope United's most-decorated player will become part of the new manager's backroom staff.
For the final four games of the season, Giggs will be assisted by Nicky Butt, Phil Neville and Chris Woods - the latter two keeping their jobs despite being brought in by Moyes.
Steve Round and Jimmy Lumsden were also brought in by the Scot but they have been fired.
Watch Manchester United v Norwich live on Sky Sports 1 this Saturday. Kick-off is at 5.30pm
Don't think he can have too many complaints, I reckon if we was in touching distance of top 4 and could see the team improving in time for next season he;d still be there. but since the turn of the year we've got worse and our record against the top 9 is embarrassing. his methods didn't work and never seemed to have any tactics. where as Rodgers tinkers with formation etc moyes just played the same sh*te hoping things would change. I want g nev to take over but maybe it needs some1 with the experience of van gaal to overhaul the squad. only thing that puts me off is he's old and never managed the fast pace of the premier league b4. having said that he's managed 2 of the biggest teams in Europe. whoever comes in, they need to get this right this time- swampdog83