An investigation report found that Police Scotland failed to categorise the Ayrshire woman as a missing person after concern was raised for her welfare.
The 38-year-old woman was found dead in her home 12 hours after police first went to the property to investigate her whereabouts, the police watchdog has found.
Officers first went to the Ayrshire house on the afternoon of December 28, 2018 after Police Scotland was contacted by an addiction service worker to say the woman had failed to attend an appointment for an important meeting with Social Services, had poor mental health and had not collected prescribed medication for four days
However, they could not establish whether anyone was at home.
The Police Investigation & Review Commissioner (Pirc) report said neighbours told the officers they had heard someone moving around inside the previous evening, which led them to assume she was alive and inside.
However when night-shift officers went to the property in the early hours of December 29, they looked through a gap in the blinds next to the front door and saw the upper body of a woman on the floor behind the front door.
They forced entry to the house and found the woman to be unresponsive. She was pronounced dead by a paramedic a short time later.
The Pirc report found a missing person report should have been created after the officers who first attended could not trace her, and that should have resulted in her home being searched.
However the watchdog found it was unlikely the death could have been prevented if officers had forced entry to the property earlier.
It also said the officers who initially attended conducted "appropriate inquiries to locate the woman".
The report said: "Entry was forced to the woman's home some 12 hours after the police initially attended at the house.
"It is unlikely if the initial attending officers had forced entry to the house on their arrival that the woman's death could have been prevented."
The report said the cause of death was the combined adverse effects of multiple use of drugs.
New approach to provide better service
Pirc said police have implemented a number of recommendations made in the report.
The recommendations include reminding officers of procedures to follow in missing person cases, and refreshing staff in the area control room on the importance of providing officers with all relevant information.
Police Scotland Assistant Chief Constable John Hawkins said: "This was a tragic death and our thoughts remain with the woman's family and friends.
"As noted by the Pirc, we have implemented the commissioner's recommendations.
"We are introducing a new approach to call assessment to ensure we can provide better service to the public by taking more information from the caller so that we can make a more robust assessment of risk, threat and harm and vulnerability to ensure every caller gets the right response."
The introduction of the Contact Assessment Model (CAM) in June provides further guidance to determine the management and oversight of calls for help from the public.