For the most typical case - say, a student who fails a class one semester - the most common action at UMN is to have them repeat that class. So no, they typically wouldn't repeat the *full* year; they'd be gone for a semester and then start up again next semester and take only the class they failed, and then they'd pick up like any other student with a full load the following semester. It can get more complicated (for instance, two D's equals an F and you'd retake both those classes), but the most straightforward cases is 'retake what you failed and then progress on'. A student may be asked to retake other classes they did poorly in, but in general it's "repeat what you failed".
This can actually work against you if you've got a large loan debt, because loan payments can kick in if you don't have at least ... what ... a half-time load? Something like that. Occasionally I've seen the school able to swing things so that you can pick up some electives in your 'off' semester - enough to keep your loans in deferment, but that really only works if you're at the right spot in the curriculum where there electives available that you could take.
I sat on our school's student promotions committee for a year, so I saw firsthand how the decision-making works, and in general, I feel like UMN is very, very willing to work with students to come up with a common-sense, reasonable remediation plan. I was super impressed with the thoughtfulness they gave the cases we saw. It was definitely not an adversarial kind of approach.
