You knew that something had to go wrong. Microsoft was not going to deliver the Mango (Windows Phone 7.1) to all WP7 device owners without a single hitch, right? We have found the fly in the ointment.

Microsoft is currently, and officially, looking into issues that users of its mobile line that have executed the update are having with accessing Office 365 and Exchange 2003. According to reports, the SharePoint Online part of Office 365 is causing problems.

Roughly half of all extant (sold before Mango was completed) WP7 handsets have been upgraded to the latest edition of the software. Assuming that this problem is endemic, and not sporadic, it is an issue that Microsoft must correct, especially given the enterprise history and legacy that its mobile devices have; in other words, Windows Phone devices sell on their cohesion with Microsoft’s enterprise products, and so if it fails, the problem is even more acute.

With Office 365, the problems have been known for several weeks. Those with the small-business version of Office 365 cannot access it, oddly enough. Why the error would be plan specific is a mystery. In regards to Exchange 2003, original messages are going missing. Exchange 2003 is now quite dated, but in use. ZDNet pinged Microsoft over the issues, and was told that the company is “investigating reports of this issue and will share more information as it becomes available.”

We are stuck in wait and see mode for now.

While these are real, and serious issues, they are not likely to cause the Windows Phone platform much material harm, as they impact current as opposed to potential WP7 handset owners. And assuming that Microsoft solves the pips on the double, this should clear quickly. Still, we knew that something had to break. It feels good to have found it.