For nearly two days, several million Blackberry owners found themselves without service. In a panic, RIM rushed to find the cause of the problem, which doubtless cannot help the company that has already come under so much scrutiny. They have found the source of the problem, they say, and it turned out to be a software update designed to increase e-mail holding space. The failure apparently managed to happen because of poor pre-testing:

”It admitted that "the pre-testing of the system routine proved to be insufficient". RIM added that the process designed to maintain the service in the event of a failure "did not fully perform to its expectations", causing a longer delay before the system was restored.”
We've all seen companies being forced to recall patches or have their customers systems disabled due to insufficiently tested changes. Despite the nuisance caused, RIM doesn't predict they will lose any customers because of this, and nor do industry analysts. Hopefully, though, they'll learn from this.