A £38 million IT and call handling system has been abandoned by NHS 24 due to concerns about patient safety.
The Future Programme was launched last month but problems quickly emerged with delays in answering calls.
Bosses have now announced it has been withdrawn and replaced with the previous system while a solution is found.
An Audit Scotland report had previously raised concerns over the cost and delivery of the system.
Initially due to be ready for October 2013, it was delayed for two years and cost around £38 million – almost £10 million above the expected cost.
A statement from NHS 24 said: “On the grounds of patient safety, NHS 24 has today withdrawn its Future Programme from service and moved back to its legacy system.
“In spite of a huge amount of planning, system testing and staff training, the performance of the service over the past 10 days since go live has proved extremely challenging.”
Work is to be carried out to fix the problems and relaunch the programme early next year.
NHS 24 chief executive Ian Crichton said: “Major IT upgrades always bring a degree of challenge, but what makes implementation of our new technology solution unusually difficult is the need to keep patients safe, while we get it fully operational.
“As winter approaches we expect weekend call volumes to significantly increase and our forecast indicates that service levels at weekends would fall below acceptable tolerances. It is for this reason that we have taken the decision today to roll back.
“While we will maintain the delivery of safe care to patients, we will continue to develop the new system offline and renew preparations to reintroduce the solution in early 2016.
“This is not a decision that we have taken lightly, given the significant investment to date, but one that will ensure we can continue to deliver vital and safe out of hours support to patients when they need it most during the coming winter.”