Scores of GCSE and A-level pupils face having to repeat an entire academic year after their school decided to fold midway through their course.
Abbots Bromley School announced in March it would shut on 5 July unless a buyer could be found.
The fee-paying, mixed site in Staffordshire says it has a funding crisis, and a purchase is not forthcoming.
Angry parents say it leaves students high and dry as exams loom.
Children in years 10 and 12 are halfway through their two-year GCSE and A-level programmes respectively, and look set to need new schools to complete their studies.
According to parents, that is proving difficult as pupils are struggling to find local alternatives that offer courses with the same exam board.
Without a match to studies already under way, they say pupils will have to start over instead and repeat years 10 and 12.
The school, which has about 200 pupils aged three to 18, says it is assisting with transfers. It is thought about 40 year 10 students are affected, with about 20 in year 12 facing similar uncertainty.
Parent Lisa Butler says her 14-year-old daughter is distraught.
"She in the first year of her GCSEs and if we can't find a like-for-like school, she will have to repeat or cram two years into one somewhere else, which is tremendous pressure and a real concern.
"It's very hard to be positive when you're in a situation you don't want to be in."
The Rugeley site is an independent boarding and day school, responsible for its own governance and finance under the umbrella of charity Woodard Corporation which owns dozens of schools and academies across England.
The school, which charges up to £15,800 a year for day students, says a potential overseas buyer's interest has cooled and there is no official offer to purchase.
But parents claim four overseas investors have contacted them via their campaign website to express an interest in buying the school and they have passed them on to the charity
A-level student Katie Barrett says she is annoyed by her situation.
"This year feels like a bit of a waste because I'm now going to have to re-do it all and obviously different exam boards mean different techniques."
Her father Stephen added: "It's heartbreaking for her having to re-do the course again."
A spokesperson for the school said losses were sustained over several years and it was short of "working capital", meaning it was unable to guarantee it would not run out of funds, resulting in sudden closure.
Therefore, she added, the school had given notice from mid-March for "orderly closure".
She said "a number of families have found schools with similar exam boards and timetables", but the governing board recognised there was an impact on some pupils in exam years.
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