Last summer Mourinho spent £150million to sign Eric Bailly, Henrikh Mkhitaryan and Paul Pogba, for a world record fee.
While Zlatan Ibrahimovic arrived on a free transfer.
But the expensive outlay has not resulted in the success anticipated.
Man United squad arrive at the Lowry Hotel ahead of derby clash Wed, April 26, 2017
Express Sport brings you the best pictures as Manchester United arrive at the Lowry Hotel ahead of Thursday's derby clash
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Manchester United arrive at the Lowry Hotel ahead of their clash with Man City
United won the EFL Cup but are fifth in the Premier League, 15 points off leaders Chelsea and were knocked out of the FA Cup in the quarter-final stage.
However the Red Devils are into the semi-finals of the Europa League, where a win in the final guarantees a place in next season's Champions League.
Nevertheless Mourinho is ready to bring the chequebook out again to spend big in the summer to ensure a stronger tilt at the major trophies.
Jose Mourinho wants to strengthen his team
According to ESPN FC, United have pinpointed three areas to strengthen.
Mourinho is said to want a centre-back and a midfielder.
Two new strikers are also wanted with the report claiming they will replace the injured Zlatan Ibrahimovic and club captain Wayne Rooney.
Chelsea attacker Willian is mentioned as a target while reports have suggested United want Antoine Griezmann and Andrea Belotti in £170m double deal.