Contacts, calendar entries, photographs and other personal information of Sidekick users has almost certainly been lost for good following a service disruption at Sidekick provider Danger, the Microsoft subsidiary said on Saturday.
The amount of data and number of users affected wasn't disclosed by Microsoft or T-Mobile, but the Sidekick support forums are buzzing with pleas from users looking for tips on how to restore their devices or get their data back.
On Saturday, Microsoft said any data that users had on their devices and is no longer there has almost certainly been permanently lost.
"That said, our teams continue to work around-the-clock in hopes of discovering some way to recover this information. However, the likelihood of a successful outcome is extremely low," T-Mobile said in a statement.
The problems have been going on since earlier this week and have been compounded by users who attempted to reset their devices to restore functionality. The reset clears the Sidekick of stored data - data which is usually backed up to the Danger servers but has now been lost from there.
"We continue to advise customers to NOT reset their device by removing the battery or letting their battery drain completely, as any personal content that currently resides on your device will be lost," T-Mobile said.
T-Mobile and Microsoft said they would provide an update on data recovery efforts on Monday.
The service failure is an embarrassment for Microsoft and T-Mobile and again highlights the potential danger of entrusting trusting personal data to the cloud, a model that many service providers are pushing as a safe and more convenient way to handle data.