A man has been arrested on suspicion of murdering a woman who worked as a chef at York University.
Claudia Lawrence, who was 35 when she disappeared, has been missing since 2009.
North Yorkshire Police confirmed the man, in his 50s, was from the York area, but said no further details would be released at this stage in the investigation.
Searches related to the case will continue over the next few days, the police said.
The force stressed that Ms Lawrence had not been found.
The senior officer in charge of the case warned the media not to identify the arrested man so as not to jeopardise the legal process.
“To ensure the investigation and legal process are not compromised or potentially damaged in any way during this critical phase in seeking the truth about Claudia's disappearance, North Yorkshire Police strongly advises the media and members of the public against identifying the man who has been arrested,” Detective Superintendent Dai Malyn, head of North Yorkshire Police's Major Crime Unit, said.
The public were also urged not to name him on social media.
The arrest comes days after police released new footage of two people walking near Ms Lawrence's home that police said could be "potentially significant".
Last year a 60-year-old man was arrested in connection with the case but was later released without charge.
Timeline of Claudia Lawrence's disappearance
March 2009 – Claudia is reported missing by her father
April 2009 – Man at Tang Hall Co-Op store says he knew Claudia
June 2009 – Claudia’s father says he still has hope his daughter will be found
June 2013 – North Yorkshire Police’s new Major Crime Unit set up
October 2013 – Major Crime Unit begins forensic re-examination of Claudia’s home using new techniques
March 2014 – New DNA evidence is discovered on cigarette butt in Claudia’s car
April 2014 – 121 people come forward to assist the police in a review of the investigation
May 2014 – A 59-year-old man is arrested on suspicion of murder
June 2014 – Arrested 69-year-old man is re-bailed
February 2015 – Detectives carry out searches in an alleyway close to Claudia’s home
March 2015 – New CCTV footage released of two people near Claudia’s home
March 2015 – Latest arrestReuse content