NHS Lanarkshire believes it is much better placed to deal with future cyber attacks.
Almost 500 appointments and procedures were cancelled when its computers were infected by the WannaCry ransomware in May.
A further cyber attack in August led to 184 cancelled appointments.
Microsoft released a security patch in March that blocked WannaCry, but a report to the board revealed it was being tested by the eHealth team at the time and was not fully rolled out.
It is believed no data was “lost or unrecoverable” and chief executive Calum Campbell praised the work of staff.
He said: “Following the cyber attack in May we took prompt and robust action to improve the security of our IT systems, which helped limit the impact of the malware incident in August.
“We apologise to any patients affected by the May and August incidents. Our staff went above and beyond during these incidents to successfully minimise the inconvenience to patients and quickly restore our IT systems.
“The integrity of our patient data was maintained in both cases and NHS Lanarkshire is now much better placed to respond to future cyber threats.”