The search for Claudia Lawrence could be being hampered by the withholding of vital information, police have said a decade after she was last seen.
Monday marks a decade since the University of York chef vanished on March 18 2009 at the age of 35.
Although no body has ever been found, North Yorkshire Police have been treating her disappearance as a suspected murder investigation.
Nine people have been arrested or interviewed under caution in connection with the investigation and police submitted files to the Crown Prosecution Service (CPS) in relation to a number of individuals, but there was insufficient evidence to bring charges.
On the tenth anniversary of when she was last seen, North Yorkshire Police said they are still waiting for information from the public to help them make major progress.
Detective Superintendent Dai Malyn said:
Following Miss Lawrence's disappearance, searches were initially focused on the route between her home on Heworth Road and the University of York.
Hundreds of officers across various forces were initially involved but the investigation has been scaled back over the years.
Mr Malyn added that the investigation has so far been hindered by a lack of CCTV around Miss Lawrence's home, as well as the fact that she had neither a smart phone or a social media profile when she vanished.
The force explained how members of the public are still coming forward with information.
Despite being "well intentioned", much of this is based on speculation or theory, Detective Superintendent Dai Malyn said.