On Saturday night Suncorp customers found their bank accounts missing money, in overdraft, and in some cases inaccessable.
By Sunday evening everything was fixed, according to Suncorp, but how did this happen in the first place?
As reported by ITNews, a "glitch" during a system upgrade is to blame, and an investigation by the bank hopes to uncover more details.
Suncorp is looking at everything - processes, procedures, the lot - that occurred in the lead-up to the event for answers and clues on how to prevent this from happening again.
CEO David Carter took to Facebook to offer an apology.
Some customers are still experiencing problems, though.