The January transfer window is a notoriously difficult time in which to do business, with desperation often leading to bad business.
Manchester United, like every club, have had their fair share of flops in the transfer market. For every brilliant one in January - think Patrice Evra and Nemanja Vidic - they have endured one that has not worked out at all.
Erik ten Hag will be trying to avoid such pitfalls at the moment. The Dutchman has already sanctioned a short-term loan deal for Burnley striker Wout Weghorst, who fills the gigantic boots of Cristiano Ronaldo.
Weghorst will set United back £2.5million in loan fees and will be keen to avoid joining the names on this list. Here Mirror Football takes a look over some of United's very worst January transfers over the years.
Alexis Sanchez (January 2018)
The first player most United fans would think of when faced with the prospect of naming the worst January signings. Sanchez joined United in a swap deal, with Henrikh Mkhitaryan moving to Arsenal.
It may have looked like a shrewd move, with Sanchez having proven himself to be one of the best Premier League attackers by contributing 80 goals and 45 assists in 166 appearances for Arsenal, but it turned into a nightmare one.
The Chilean commanded a huge pay packet, worth a reported £400,000-a-week, but struggled to transfer his Arsenal form to Old Trafford. He managed just five goals and nine assists in 45 games before being shipped out on loan to Inter Milan 18 months later.
Dong Fangzhuo (January 2004)
A very strange transfer from Sir Alex Ferguson. Dong arrived from Chinese side Dalian Shide for an initial fee of £500,000 that could've risen to £3.5m depending on appearances.
It didn't work out, but at least United didn't have to fork out the full fee, with Dong making just one Premier League outing in three-and-a-half years at the club. Royal Antwerp benefited, with the Chinese international scoring 34 goals on loan in Belgium.
Dong lived the life of a journeyman, going to Poland, Portugal, Armenia and China before retiring in 2014.
Manucho (January 2008)
Manucho arrived on a three-year contract after banging in goals for Angolan outfit Petro Atletico and impressing on trial. Needless to say it didn't work out.
He made just one Premier League appearance for Ferguson's side before loan spells at Panathinaikos and Hull City. Manucho had a decent career with Real Valladolid and Real Vallecano in Spain and managed 22 goals in 53 games for Angola, but is a mere footnote in United's history.
Diego Forlan (January 2002)
Another striker signed in January, another one who didn't bring home the goals. Forlan was just 22 at the time and came highly rated. His successful career after United perhaps suggests it was just a case of the right player at the wrong time.
The Uruguayan did contribute 17 goals and nine assists in 97 games but never really settled in two-and-a-half years at Old Trafford. He left for Villarreal in 2004 and immediately banged in 25 LaLiga goals in a season before going on to have a great career elsewhere.
HAVE YOUR SAY! What is the worst January transfer Manchester United have ever made? Comment below.
Victor Valdes (January 2015)
Valdes arrived at United after a long period of injuries. He ended up making just two appearances in 18 months as the back-up to David de Gea.
The veteran goalkeeper left under a cloud after falling out with Louis van Gaal, who accused him of refusing to play for the reserves. "He doesn't follow my philosophy. There is no place for someone like that," Van Gaal said in July 2015.
United failed to move him on that summer, before sending him on loan to Standard Liege in January 2016. He was then sold to Middlesbrough.
Zoran Tosic (January 2009)
United thought they had signed Serbian youngsters Tosic and Adem Ljajic from Partizan Belgrade in January 2009, only for Ljajic's move to collapse.
Tosic played just twice in the Premier League, was loaned to Koln and then sold to CSKA Moscow in a remarkably short stint. He won three Russian Premier League titles with CSKA and at the age of 35 is still playing for Tobol in Kazakhstan.
Ritchie De Laet (January 2009)
De Laet was signed from Stoke City on a three-year contract. He went on to make 27 appearances for the under-21s, but just six for the first team.
The Belgian defender was loaned to Sheffield United, Preston, Portsmouth and Norwich and then sold to Leicester, where he spent four years. Now 34, De Laet is still playing for Royal Antwerp in his native country.
Sadiq El Fitouri (January 2015)
Phil Neville is the man responsible for El Fitouri's uninspired time at United. The defender was training with Salford City when Neville arranged for him to have a trial at United.
He was signed on an 18-month deal, but failed to make a first team appearance for United and then signed for Chesterfield in January 2017.
Now 28, he has since played for Libyan side Al-Ahli Tripoli, Romania's FC Politehnica Lasi and Sudanese side Al Hilal.