Yahoo has responded to claims that its email service was the root cause for phantom data issues on Windows Phone 7 devices, admitting that although Yahoo Mail was causing issues for Windows Phone 7 customers, it was actually Microsoft’s implementation of IMAP for the service that encouraged excessive data use.

In a statement, the company noted:

“Yahoo! Mail is widely available on tens of millions of mobile phones, including those running on Apple iOS, Android, Nokia Symbian, and RIM. The issue on the Windows Phones is specific to how Microsoft chose to implement IMAP for Yahoo! Mail and does not impact Yahoo! Mail on these other mobile devices. Yahoo! has offered to provide Microsoft a near-term solution for the implementation they chose, and is encouraging Microsoft to change to a standard way of integrating with Yahoo! Mail, which would result in a permanent fix.”

This wording of the statement suggests Microsoft has been hasty in its IMAP implementation, with Yahoo resorting to “encouraging Microsoft to change to a standard way of integrating with Yahoo! Mail”. If we were to join the dots here, Microsoft’s initial statement has put Yahoo in a tight spot and the company is using a tersely worded statement to assert the fact it was not specifically at fault.

For Microsoft, it’s more publicity it could do without, especially with accusations that Bing engineers have been using Google’s search results to boost its search engine.

Whilst a temporary solution has been offered, Microsoft has stated it will release an update that should patch the issue in the next few weeks. This should be incorporated into the first major Windows Phone 7 update, expected later this month.