Microsoft Sidekick users lose data

Users of the Sidekick – a mobile phone and emailing device popular with celebrities such as Paris Hilton – were told that crucial personal data, such as contacts, calendar entries, appointments and photos, were lost as a result of a server failure at Danger, the company that makes the device, and which was acquired by Microsoft last year.

"Our teams continue to work around-the-clock in hopes of discovering some way to recover this information," said T-Mobile and Microsoft in a statement. "However, the likelihood of a successful outcome is extremely low."

The one million users of the device have been warned not to reset the phone, or let the battery run out, as it may result in any remaining data being permanently lost.

The data loss has led some experts to question the integrity of so-called "cloud computing" services, where information is stored on a remote server rather than on the device itself. The Sidekick relied heavily on cloud backups, with everything from instant-messaging to emails stored remotely, and the handset itself containing only a cached version of the most recently synchronised data.

Microsoft was handling the storage of this data in its data centres, and traditionally, backups of this data are also made at other sites to ensure that data remains accessible should a server centre experience a power outage or natural disaster.

But a spokesman for Microsoft told Reuters that a "confluence of errors" from the server failure impacted both the main and backup databases.

T-Mobile is offering Sidekick users a $20 (£12) refund to cover the cost of one month of data usage on the phone. It also will give customers who experienced a "significant and permanent" loss of personal data a $100 (£63) "customer appreciation" voucher which can be put towards other T-Mobile products and services, or used against a phone bill.

The data loss is an embarrassing blow for Microsoft, which is looking to put more of its products and services "in the cloud", including its Office suite of products.

Google already offers a similar service through Google Docs, which enables web users to write, edit and collaborate on spreadsheets and Word documents through their browser window.