Police and prosecutors are still sharing evidence on computer discs, leading to sensitive information being lost.
A joint report by two watchdogs found that information including the testimony of vulnerable and underage victims and witnesses, known as Achieving Best Evidence interviews, was carried around on disc.
In one case, the DVD of an interview of a 12-year-old victim of a sex offence was lost and a new tracking system for evidence had to be introduced.
Inspectors from HM Crown Prosecution Service Inspectorate (HMCPSI) and HM Inspectorate of Constabulary (HMIC) also found that some police forces were using computer systems that had been in place for up to 20 years.
The report, which looked at criminal justice computer systems, said: "We were concerned to learn that a widespread issue existed concerning the Crown Prosecution Service (CPS) misplacing discs containing sensitive evidence and information, such as CCTV, 999 recordings, suspect interviews and, more alarmingly, Achieving Best Evidence (ABE) interviews. Many officers informed us that it was common to receive several requests from the CPS to supply further copies of discs because the original copy submitted could not be found."
A system used for police to share files with prosecutors is only able to handle individual documents or attachments of less than 1MB, which the report said was "a significant barrier".
The inspectors, who visited six forces and their corresponding CPS regions, said police and prosecutors need "to urgently review arrangements for the handling of hard media".
It also cited one case where the CPS was fined £200,000 by the Information Commissioner's Office in November 2015 after laptops containing videos of police interviews with victims and witnesses were stolen from a private contractor's studio.
Millions of pounds have been spent trying to improve the use of electronic systems in police forces and the courts, including the £98 million Criminal Justice System Efficiency Programme, and the Criminal Justice Common Platform IT programme which cost £30.5 million to August 2015. UK police forces were expected to spend £492 million on IT in 2015/16.
The report said that some forces were using systems that had been in place for up to two decades, and that victim and witness statements were generally handwritten by officers and then scanned into a computer, which "often made the documents difficult to read".
However the inspectors said that "good progress" had been made towards a full digital system, and highlighted examples of the installation of wi-fi in magistrates' courts, an online charging facility and a prosecutor app which allows cases to be updated from court in real time.
The watchdogs visited police forces in Kent, Merseyside, Greater Manchester, Northamptonshire, West Midlands, and the Metropolitan Police, and inspected the corresponding CPS regions in the South East, Merseyside and Cheshire, North West, East Midlands, West Midlands and London.
They also observed magistrates' and Crown court cases, and interviewed representatives from the police, CPS, courts service, Ministry of Justice and Home Office.
They praised a scheme where witness care staff in Greater Manchester were able to work from home using remote technology, and use of video links in court by Kent and the Met.
A collaboration in the East Midlands among Leicestershire, Lincolnshire, Nottinghamshire and Northamptonshire using the same IT system was singled out as good practice, as were police-led prosecutions for driving offences being presented by an officer via videolink from a police station to a magistrates' court.
A CPS spokeswoman said: "The CPS is already working, with its partners, to create a unified digital case management system, which when completed will make the use of discs obsolete.
"In the meantime, new standards have been developed for the handling of electronic hard media. CPS areas are working closely with their local police forces to jointly review their handling and transportation of such material."
The sensitive material on the stolen laptops was not accessed and the CPS said it had strengthened arrangements for handling sensitive material after the theft.