iOS 6.1 issue with Exchange 2010 EAS Calendar Syncing

As most of you are probably aware by now, Microsoft & Apple are actively investigating the latest reported issue with iOS 6.1 users syncing with Exchange 2010 ActiveSync. 

Microsoft has released a KB article that details what we know so far:

Apple has also recently released a support article for this issue:


*UPDATE: Apple has released 6.1.2 ( which should address the 6.1 issue.    


Essentially the symptoms we've seen so far are excessive log growth, resource consumption on Client Access & Mailbox servers, and performance-related problems due to high memory and/or CPU increases.

Here are a few of the workarounds we've been using thus far:


Install 6.1.2 update from Apple to resolve the issue:


Identify iOS 6.1 Devices

To identify the issue in your environment, the process I've been using thus far is parsing through IIS logs.  The easiest way to do this is to use a tool called Log Parser Studio.  If you haven't been using this great tool, download it here:

Log Parser Studio has several built in queries to collect ActiveSync information, such as the ActiveSync Report.  Any 6.1 devices should be noticeable by locating the User-Agent field, which will look something like the following for iOS 6.1:

  • Apple-iPad3C3/1002.141
  • Apple-iPhone4C1/1002.142

To create the query to check specifically for the iOS 6.1 issue (from the KB Article), open Log Parser Studio, click File, New, and Query

Then paste the following query (also in the KB) into the New Query window:

   Cs-username AS User,
   MyDeviceId AS DeviceId,
   COUNT(*) AS Hits
   EXTRACT_VALUE(cs-uri-query,'DeviceId') AS MyDeviceId
WHERE cs-uri-query LIKE '%Error:WrongObjectTypeException%'
GROUP BY DeviceId,User


Now click File and Save Query (if you wish to save this new query).  Otherwise at this point you can load your IIS logs into Log Parser Studio and execute the query. 


Here are the list of iOS UserAgents to be on the lookout for:

6.1 1002.141

-or 1002.142

-or 1002.143

-or 1002.144

6.1.1 1002.145

6.1.2 1002.146

----or 1002.147



This Exchange Shell command should help you locate iOS 6.1 devices as well if you don't have Log Parser Studio:

Get-ActiveSyncDevice | where {$_.DeviceOs -match “iOS 6.1″}



*UPDATE from the Apple KB:

Apple has identified a fix and will make it available in an upcoming software update. In the meantime, you can avoid this bug by not responding to an exception to a recurring event on your iOS device. If you do experience the symptoms described above, disable then reenable the Exchange calendar on your iOS device using the steps below.
1. Go to Settings > Mail, Contacts, Calendars
2. Select the Exchange account from your Accounts list.
3. Turn the switch for Calendars to OFF.
4. Wait ten seconds.
5. Turn the switch for Calendars back to ON.


**UPDATE: Apple has released 6.1.2 ( which should address the 6.1 issue.