In the latest incident customers took to social networks to complain that their wages were not in their accounts and they were having problems accessing their online services.
When one disgruntled customer suggested switching accounts, Ulster Bank replied in a tweet saying: "Please don't break our heart :( Our team is working very hard to rectify this as soon as possible ..."
By Thursday lunchtime the bank said the issue had been resolved and customers left out of pocket would be compensated.
It said the problem affected its euro accounts and the issue would not have had a "major impact" on Northern Ireland customers.
A spokeswoman added: "Some files were delayed through our payment system overnight and these payments have now been made.
"We apologise for this delay and if any customers have been left out of pocket, we will put this right."
This is the third time this month the bank has been hit with computer problems.
Just days ago, Ulster Bank customers were affected by a 'cyber attack' on its sister company NatWest.
And that came after an earlier unconnected problem which left hundreds of thousands of people unable to use their debit or credit cards.