Sidekick owners may want to give their phones the boot after an outage this weekend cost them all the personal data they stored on the phone, including contact numbers.
Data from those phones is stored on remote servers that are managed by Microsoft, but over the weekend the servers failed.
T-Mobile, which distributes the phones, and Microsoft, say many Sidekick owners' information is "almost certainly" gone after a failure of servers wiped the data out. The companies said they hoped to update customers on recovery efforts Monday.
The phones have been troubled by data outages for more than a week. Some users attempted to restart their phones by removing the battery, which erases data on the device. Normally, the data is then restored from servers, but with the server data gone, the device was left empty.
Because of that, customers are being advised not to let the battery completely run down either.
It's not clear how many customers have been affected, or how many Sidekicks are in operation. The phone has never been a huge seller, but it's very popular among young, urban customers, and it has had a certain cachet as a celebrity phone. Most famously, Paris Hilton used a Sidekick. Users have appreciated its large QWERTY keyboard for text messaging, a feature now copied by mainstream phones.
Microsoft bought Danger Inc., the maker of the Sidekick, last year in an attempt to revitalize its "smart" phone software portfolio.