Salesforce.com Inc. (CRM), the online business-applications company, Tuesday suffered an outage that left thousands of businesses without access to data and applications.

The problem, caused by a network failure, affected all of the San Francisco company's world data centers for around 40 minutes. Salesforce.com has just under 60,000 customers, the company had said in November, although it didn't immediately comment on whether all of those were affected.

While the outage was resolved quickly, the problem underscores concerns that could make large corporate customers reluctant to embrace the "software as a service" model espoused by Salesforce.com.

The system should have triggered a "failover," allowing other redundant data centers to take over after the main ones failed, but this didn't happen. Staff eventually manually restarted the data centers.

In a message on the company's Website, Salesforce.com said it was "confident the root cause [of the problem] has been addressed by the work-around."

Salesforce.com said its technology team was working with hardware vendors to fully explain the problem, and would update its customers.

The company allows business customers to host applications and data on Salesforce.com's own servers, minimizing the need for costly and time-consuming software updates. Users pay for the applications and services on a per-use basis.

While shutdowns like this are rare for Salesforce.com, one IT security specialist, who didn't want to be named, said that they posed significant security risks for the company's customers. A shutdown of even 40 minutes could potentially infect thousands or tens of thousands of customers with viruses, this person said. Salesforce.com didn't immediately respond to a question about whether the outage led to any security breaches.

-By Jessica Hodgson; Dow Jones Newswires; 415-439-6455; jessica.hodgson@dowjones.com

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