She called her mom screaming, “I got in! I got in!” Then she told all of her friends. “She was ecstatic. She was so happy,” said her mother, Margaret Zalenska of Northern Virginia. “It was her dream college.”

Then Vassar admissions officials realized they had made a mistake. They had accidentally posted an acceptance letter where a denial letter should have been. By the time the mistake was corrected about 30 minutes later, 76 students had incorrectly been told they had gotten in.

“Each of those students was informed of the error and received our deepest apologies,” said Vassar President Catharine Hill in a statement. ”We are full of regret and we will be making changes to our notification system.”

In the emotional admissions process, the biggest mistake that a college can make is accidentally accepting students it meant to deny. Yet, every year the nightmare situation hits at least one college, especially as schools handle record numbers of applications and rely more heavily on automated computer systems.

One of the most epic gaffes was in 2009 when the University of California, San Diego, admissions office sent acceptance e-mails to all of the 46,000 students who had applied, including the 28,000 who had not gotten in. On April Fools Day of that same year, New York University mistakenly congratulated 489 students who had been rejected. The next year, George Washington University accidentally welcomed about 200 students to the Class of 2014 — even though those same students had just been rejected.

When Northwestern University accidentally accepted 50 graduate students in 2008, it refunded their application fee as an apology. Vassar announced over the weekend that it will refund the $65 application fee paid by the 76 students who were accidentally accepted, according to The New York Times.

An admissions expert told me in 2010 that if only a few students have accidentally been admitted, some schools will quietly honor those acceptances, as long as the students meet admissions requirements. But if the number is in the dozens or hundreds, schools have to profusely apologize and endure a wave of negative publicity.

As for Bianka Zalenska, who was also accepted early to the University of Mary Washington, her mother sent an e-mail to Vassar explaining how their mistake crushed her daughter.

“I just don’t understand how this prestigious institution could make this unkind mistake,” Margaret Zalenska said. “It was not a happy day.”

Related article:

On Parenting: Vassar un-accepts 76 students, parents overreact

For more higher education news, follow me on Facebook and Twitter. And for more advice on college admissions, check out the Post’s higher education page and these articles:

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Why is tuition high? Because you want it to be.