GLASGOW University has apologised for the second year in a row after problems with a £14million online registration system.
Students were unable to register for courses using the controversial MyCampus system.
Some took to social networking sites such as Twitter to complain, with one stating: "Another splendid display of incompetency from Glasgow Uni. Bravo."
"Don't even see the point in attempting to enrol for 4th year. MyCampus is a joke," stated another.
Another said: "The only thing you can rely on with MyCampus is its consistent ability to fail to provide its most basic services."
Officials said it was unclear how many students are affected, or what the underlying problem is.
The university advised students to wait for an email from the university before trying to re-register.
An urgent investigation is being held.
A university spokeswoman said: "A number of students have experienced problems when trying to register online for the next academic session The university is sorry for any inconvenience caused.
"We will advise all students as soon as this is resolved."
Last year, thousands of students called a university helpline to complain about glitches that left them unable to register for courses.
Common complaints included students being enrolled for the wrong degree or told compulsory classes were full.
Following the debacle, computer specialists from the university warned the disruption was likely to be repeated this year because of flaws in the system.
An email summarising the view of computer science specialists described the system as "unintuitive, riddled with errors and extre-mely difficult to use".
It added: "This is not a teething problem and therefore likely to recur every year."
The UCU lecturers' union said the system is "cumbersome, frustrating and unreliable".