Microsoft and T-Mobile have released an online tool that the companies say will allow Sidekick mobile device users to recover data lost during a server outage last week.

"Log into the My T-Mobile Web site, where there will be a recovery tool to restore contacts you may have lost during the recent service outage," Microsoft said in a statement Tuesday.

The catch: Microsoft said the tool will only restore data that users had stored as of Oct. 1. And, as for now, only information on personal contacts has been recovered.

"With a few clicks and a confirmation, you will be able to restore these contacts to your Sidekick. If you have recreated some of the same contacts on your Sidekick since October 1, you can choose to keep both sets of contacts, merge them, or just keep the set of contacts now on your device," said Microsoft.

Microsoft said it's still restoring other forms of user data lost during the outage, such as calendar entries, to-do lists, notes, and gaming high scores.

"We continue to work 24 hours a day, 7 days a week to restore your data," said Microsoft. "We're making solid progress on the next phase in this restoration process," the company said. "We appreciate your ongoing patience," it added.

Microsoft has said it believes data loss affected only a minority of Sidekick users, while various reports indicated that users who had reset their devices during, or just prior to, the outage were mostly likely to have been victimized by the problem.

A Microsoft executive said in a statement last week that the company, along with network partner T-Mobile, was taking steps to ensure that similar problems don't re-occur in the future.

"Specifically, we have made changes to the overall stability of the Sidekick service and initiated a more resilient backup process to ensure that the integrity of our database backups is maintained," said Roz Ho, Microsoft's VP for Premium Mobile Experiences.

The reassurance didn't satisfy all users, however. The incident has prompted at least one class-action lawsuit against Microsoft and T-Mobile.

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