All the big clubs across Europe's top 5 leagues have a number of disappointing transfers they would love to erase from their history. In the Premier League, for instance, Manchester United are a perfect case study.The Red Devils have maintained their status as the biggest outfit in England for several decades. With cash flowing in consistently, spending big in the transfer market to sign elite superstars has never been an issue. The concern, however, is that many of these high-profile signings never stepped up at Old Trafford.From being the undisputed superstars of their former teams to becoming mere shadows of themselves at Manchester United and eventually leaving in frustration, things happened quickly in the careers of these players.Most such cases were recorded at the beginning of the post-Ferguson era. The Red Devils responded to the retirement of their legendary manager by investing a lot of money into their squad. The plan was to keep the club where it belonged among Europe's elites. Unfortunately, it never came to fruition.Without further ado, let's take a look at 5 high-profile signings who flopped at Manchester United in recent years.#5 Memphis DepayThe winger flopped badly at Old TraffordThe attacker was lured to Old Trafford in the summer of 2015 following a prolific outing for PSV Eindhoven during the 2014/2015 campaign in which he bagged 28 goals and eight assists in 40 appearances for the Eredivisie side across all competitions.Memphis Depay was signed for €34 million. He was given the iconic #7 jersey worn by players like Cristiano Ronaldo and David Beckham at Old Trafford. That further raised expectations on the shoulders of the Dutchman."They say I flopped - but I drive a Rolls Royce" - Memphis Depay defiant on Man Utd spell | @MullockSMirror https://t.co/qYVFlDN0yY pic.twitter.com/YrtiGIiaE9— Mirror Football (@MirrorFootball) June 26, 2021Unfortunately, the winger couldn't take advantage of the opportunity. He scored just twice in 29 appearances in the Premier League during his debut campaign and only once in the Champions League. That was followed by a fruitless outing in the subsequent campaign, forcing Manchester United to offload him to Olympic Lyon halfway through the season for a paltry €16 million.#4 Henrikh MkhitaryanManchester United eventually swapped this flop for anotherMkhitaryan joined Manchester United from Borussia Dortmund for €42 million in 2016. Given his eye-catching displays in the Bundesliga prior to the move, the attacking midfielder was expected to light up the Premier League but he failed to deliver.Henrikh Mkhitaryan leaves Manchester United after 63 appearances and 13 goals.Wish it had ended on a higher note... He is a true gentleman and professional!Thank you for the Europa League trophy and of course THAT scorpion kick! All the best of luck @HenrikhMkh 🔴⚪️⚫️ #MUFC pic.twitter.com/MvNMEfdeY5— Hêlîn (@MUnitedGirl) January 22, 2018The Armenian's stint at Old Trafford proved to be disappointing. He couldn't replicate the kind of performance that convinced Manchester United into luring him to Old Trafford. He bagged 13 goals and 11 assists for the Red Devils before and was later sold to Arsenal for €34 million in January 2018.