Consider the following scenario. A Microsoft Exchange Server 2003 user sends an email message that contains Internet Calendar (iCal) parts to an Exchange Server 2010 user. The Exchange Server 2010 user downloads this email message by using Exchange Web Services (EWS) or an IMAP client. In this scenario, the iCal parts contain invalid entries. Therefore, certain functions that require iCal do not work.
For example, the Accept button and the Decline button are missing in a meeting request. Or, the TimeZone property contains a carriage return line feed (CRLF).
To resolve this issue, install the following update rollup:
2579150 Description of Update Rollup 4 for Exchange Server 2010 Service Pack 1
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information the TimeZone property, visit the following Microsoft website: