Up to 9,000 pupils in Edinburgh are being told to stay at home over concerns about the safety of a number of buildings at 17 schools.
Officials say serious issues have been discovered following storm damage to one primary school in January.
All the buildings were constructed under the same public private partnership deal.
Leader of the city council Andrew Burns says they are doing what they can to stop children missing out.
He said: "We will put in alternative arrangements for teaching as quickly as possible.
"We will prioritise S4 to S6 pupils, they have got exams coming up in a few weeks' time and that will be our absolute top priority."