Users got frustrated on Monday (February 11) when there was a three-hour email outage as they tried to access email on their Crackberries.

The cause? According to a report by the Associated Press, an upgrade designed to increase capacity was the culprit.

Despite the cause, RIM — the company behind the Blackberry device — said upgrades like this had caused no problems in the past and cannot explain why it happened this time.

The outage caused a delay for users beginning at 3:30 p.m. EST, but only affected a portion of North America, reports the AP, while others reported no interruption at all.

The Blackberry blackout was the second major outage in less than a year. In April 2007, a minor software upgrade crashed the system for all users… and another disruption in September also was caused by a software glitch.

Despite the temporary problem, no emails or text messages were lost said RIM.

“Those types of issues occur so often … they slide under the radar,” Chris Ambrosio, director of wireless research at Strategy Analytics, told the AP.

Even with the outages as of late, RIM is cleaning up. They’ve added 1.65 million subscriber accounts in the quarter that ended December 1, and now have a total of 12 million subscribers worldwide.