The problem for RBS - and frankly most of the other big banks - is that it has been under investing for years in the IT infrastructure. These are the back room computers that make all this work normally.
In fact, a lot of the systems date back to the 1980s or 1990s and one former RBS IT executive described to me a "culture of fear" within the teams there. They don't want to touch these systems because often when they do, they break.
RBS says it is tackling the IT problems, it's investing an extra £450m but with this latest collapse happening just as the Christmas spending really begins to gear up, they might be wishing they out that money in some time ago.
More top news
European nations are collectively consuming more fish than its waters can provide, according to a new study.
PM announces funding will be made available for a memorial dedicated to the victims of last week’s terrorist attack in Tunisia
Mother of the gunman in the Tunisia beach terror attack said her son once refused to kill a mouse because he "couldn't kill anything".