An Educate Together primary school has been forced to delay opening by a year, just a week before kids were due to start there.
The school in Castlebar was set to open next week, but had to delay after the Department of Education refused to allow them to move from a proposed building.
Educate Together say that the building was unviable as a long-term option, and that they had been looking for alternative options for some time.
Around 10 children were due to start at the school next week, and Jarlath Munnelly from Educate Together says this will create a big headache for parents.
"I've spoken to some of those parents and I can't tell you how let-down they are, they really feel that they have been let down and they pinned their hopes to the school and they put their faith in it and they feel let down," said Mr Munnelly.
"And if people think this is a bad news story, which I think it is, it's particularly so for the parents of the kids who had their hearts set on starting in the school, and it's difficult for them at this time to go seeking alternative schools at this stage."