Admins await an Apple fix to an iOS 6.1 Exchange bug that zaps server resources and knocks out mobile e-mail access.
The iOS 6.1 bug generates an abnormally high amount of transaction logs when an iPhone or iPad user syncs a mailbox using Exchange ActiveSync. It can also drain memory and CPU, degrading performance and eventually disconnecting the device from the server.
Microsoft and Apple have both acknowledged the iOS 6.1 bug, which affects Exchange Server 2010 Service Pack 1 and higher, as well as Office 365’s Exchange Online. Problems appear to occur when a user responds to a single instance of a recurring calendar invite.
How to Avoid the iOS 6.1 Bug
After identifying iOS 6.1 devices, an administrator has several options to combat the problem:
- Block iOS 6.1
- Isolate iOS 6.1 users in a separate database and turn on circular logging
- Implement throttling policies, which may provide mixed results
Until Apple issues a fix, Microsoft suggests throttling or blocking iOS 6.1 devices or instructing users to remove and re-add their Exchange accounts from their devices.
Apple recommends that users turn their Exchange calendars off, wait 10 seconds, and then turn them back on using the following steps:
- Access the Settings app
- Go to Mail \ Contacts \ Calendars
- Switch off the calendar in any Exchange account
- Re-enable the calendar after 10 seconds
As long as a user does not respond to any calendar invitations using the device running iOS 6.1, the device itself will not cause excessive transaction logs to be generated.
Apple released iOS 6.1, a relatively minor update, on January 28. Specific adoption figures are not available, but as of this week, iOS 6.1 accounted for 65% of all iPhone and iPad Web traffic, according to online advertising firm Chitika.
Senior Systems Engineer