THE north's exams board has apologised to pupils after its website crashed - denying them last-minute access to past papers.
Thousands of young people are sitting GCSEs and A-levels set by the Council for the Curriculum, Examinations and Assessment (CCEA).
Pupils were left angry and frustrated on Sunday when they were unable to view subject microsites and past papers.
Maths, religion, technology and business studies are among the GCSEs being taken this week, while A-levels include chemistry, English literature and German.
There are about 2,000 past papers on the CCEA site, which was offline from about 11am until 10.30pm on Sunday.
Teachers and pupils shared their concerns.
Alistair Hamill, head of geography at Lurgan College, said the loss of service was serious in the middle of exams.
"I am aware that computer systems can go down. But what is unacceptable is the lack of updates during the day. Pupils are stressed enough never mind having this degree of uncertainty to deal with too," he said on Twitter.
John Ewing, a sixth form pupil at Bangor Grammar School, said the crash affected his preparations.
"Most of my revision has been done, but I do past papers at the very end to sharpen up with still three days to go. I had the papers printed, but it was the mark schemes I needed," he said.
"I think it's very important to be going over the exam style of question close to the exam, and it is very stressful if the website is down because you don't know where you're going wrong and how to fix that."
CCEA said it immediately began work to investigate the cause and restore service.
"We contacted our third party service provider to assist us in resuming services as quickly as possible. It became obvious that the issues were serious and complex and would take time to recover," as spokeswoman said.
"CCEA staff worked consistently throughout the day to resolve the technical issues and communicate progress to the public.
"We sincerely apologise for the disruption in service. CCEA are fully investigating this matter with our service provider to ensure that this issue does not arise again."
