Microsoft has said the third party that is responsible for the mysterious "phantom data" exchange in some of its Windows Phone 7 handsets is Yahoo.
BBC quoted a statement for Microsoft saying that the company has determined that an inefficiency exists in the synchronisation of e-mail between the Windows Phone mail client and Yahoo Mail.
The glitch was first noticed early this year when some users, mostly in the US, complained that their phones running on Windows 7 exchanged data without their knowledge.
The statement said the error is in the code which tells the phone how to get new messages from Yahoo Mail. The error causes the system to download up to 25 times more information than is required.
Microsoft had previously refused to name the third party which it suspected to be responsible for the glitch.
Microsoft said it is in touch with Yahoo, and is still working on finding a fix.
