A software glitch affecting the Royal Bank of Scotland (RBS) and its subsidiaries, Ulster Bank and NatWest, has left a "large number" of customers unable to access their funds, according to BusinessWeek. The problems began last Tuesday as a result of a system outage that left a rolling backlog of transactions unprocessed. It's this backlog that's troubling RBS now — the company has been working on balancing the transactions since the error occurred, and will continue to work into the evenings and the weekend, but customers have already been thoroughly inconvenienced. A woman named Louise Collins told BusinessWeek that the bank has shown her balance as zero since last Tuesday, and that she hasn't been able to access any of her funds since. While no technical details surrounding the error have emerged, the bank is hoping to have everything sorted by Monday of next week.