When iOS 6.1 was released a few weeks ago, it came with a few serious bugs. One, the 3G connectivity issue on iPhone 4S models, was fixed with this weeks iOS 6.1.1 update. Another serious flaw was not remedied however, the bug that causes iOS devices running 6.1 to continuously loop when synchronizing a recurring calendar meeting invitation on Microsoft Exchange.
When a user syncs a mailbox by using an iOS 6.1-based device, Microsoft Exchange Server 2010 Client Access server (CAS) and Mailbox (MBX) server resources are consumed, log growth becomes excessive, memory and CPU use may increase significantly, and server performance is affected. Additionally, Office 365 Exchange Online users receive an error message that resembles the following on an iOS 6.1-based device: Cannot Get Mail, The connection to the server failed.
Microsoft suggests a few workarounds for this issue while we wait for Apple to fix the bug. It told customers to “not process Calendar items such as meeting requests on iOS 6.1 devices. Also, immediately restart the iOS 6.1 device.” Microsoft provided instructions for removing, and recreating the device partnership, creating a custom throttling policy for iOS 6.1 users, or blocking iOS 6.1 users completely.
Microsoft stated that it is working with Apple in order to resolve the issue, and recommended that customers experiencing the issues “open an Enterprise Support case with Apple”:
Apple and Microsoft are investigating this issue. We will post more information in this article when the information becomes available. Currently, we recommend that you open an Enterprise Support case with Apple, either through an Enterprise agreement or through a ”Cross-Platform Integration and Command-Line Interface” pay-per-incident case to report and diagnose the behavior in iOS 6.1.
The full list of workarounds can be viewed in the Microsoft support document.