NEW YORK — After two days of silence about a lengthy outage in its BlackBerry e-mail service, the company that makes the addictive mobile device issued a jargon-laden update indicating that a minor software upgrade had crashed the system.

The statement Thursday night by Research in Motion Ltd. said the outage from Tuesday evening into Wednesday morning was triggered by "the introduction of a new, non-critical system routine" designed to optimize the cache, or temporary memory, on the computer servers that run the BlackBerry network.

RIM said "the pre-testing of the system routine proved to be insufficient."

The failed upgrade apparently set off a domino effect of glitches, which the company referred to as "a compounding series of interaction errors between the system's operational database and cache."

The Canadian company said a "failover process" to switch to a backup system "did not fully perform to RIM's expectations." That led to a delay in restoring service and "processing the resulting message queue," a reference to the backlog of undelivered e-mail that accumulated during the outage.

While most of the outage happened outside "work" hours, the always-connected mentality fueled by BlackBerry's success left many users feeling disjointed and aggravated when their devices stopped buzzing.

Grumbles were heard at the highest levels of business and government, including the White House and the Canadian parliament.

The outage and the company's delayed, tightlipped response to the situation angered some customers. It is an approach RIM has taken with past service outages, which in fact have been rare.

Jim Balsillie, RIM's co-chief executive, downplayed the criticism of the company's communications as "a trifle unfair," because the focus was on restoring service, and the primary means of contacting users was unavailable.

"The issue is just how do you tell people what it is when it is e-mail that people are counting on, and that very communications path is down," Balsillie told the Associated Press.

Furthermore, he said, there was no information to disseminate until the cause was identified.

"Once we had the facts, we made sure they were available," he said. "People got a very accurate characterization of what it was."

Yet with the company rapidly expanding beyond its longtime focus on business users — the new BlackBerry Pearl has been a smash hit with consumers since its launch last summer — some experts say RIM needs to get more savvy in dealing with problems.

"So far, all we have gotten from RIM are explanations fit for engineers, not customers," said Richard Levick, whose firm Levick Strategic Communications LLC specializes in crisis communications.