A few weeks back we saw the issue of phantom data usage with Windows Phone 7 smartphones and it turns out that the problem was indeed real and it was being caused by Yahoo! Mail and the Windows Phone Mail client. That said, according to the statement issued by Microsoft;
We have determined that an inefficiency exists in the synchronization of email between the Windows Phone Mail client and Yahoo! Mail.
This inefficiency can result in larger than expected data usage for a very small percentage of users.
- Microsoft and Yahoo! have worked together to identify a fix, which will be rolled out in the coming weeks.
- In the meantime, customers can mitigate this issue by following these steps:
1. On the Start screen of Windows Phone 7, click on the arrow at the top right
2. Choose “Settings” from the app list
3. Choose “email & accounts”
4. Choose “Yahoo! Mail”
5. Click on the setting under “Download new content”
6. Select a less frequent setting. If you are using the default setting (every 2 hours), change this setting to ‘manually’
7. Click on the setting under “Download email from”
8. Select a shorter time range. If you are using the default setting (the last 2 weeks), change this setting to ‘the last 7 days’
Microsoft has also identified an issue with our Exchange ActiveSync [EAS] email synchronization protocol that may affect a very small percentage of users
- This issue can be caused by email that exceeds the mail server email size setting or is sent to an invalid email address
- This issue can potentially affect email services that utilize the EAS protocol – Outlook and Gmail for example
- The immediate mitigation is for users to delete mail that appears “stuck” in the outbox
- This is currently scheduled to be fixed in a near-term end user update from Microsoft
Via [Windows Phone Secrets]