Microsoft Exchange Server related News and Articles

• Meeting invites (adding tentative meetings to your calendar)
• Meeting updates (updating details in your calendar)
• Task updates
• Message recall (when someone recalls a message you've received)
• Responses to voting buttons (when you sent a mail with voting buttons, this adds the voting responses back to the original item)

The sniffer is introduced from outlook 2000 onwards. However, the way it handled in outlook 2007 is slightly different, but the work it do is the same as far as my understanding.

The outlook sniffer runs as a MAPI idle process. This means the sniffer will not process when outlook downloading emails from the server, where as it processes if you are composing and email. So if the outlook is busy due some MAPI activity, which can be due to a third party add-on, the sniffer may not trigger and you will not get the necessary output as desired.

Hope we all are on the same page about the outlook sniffer. Now let us see what happens to a Meeting Request when the outlook sniffer acts on it. When a new Meeting Request arrives in your outlook inbox, sniffer marks it in the outlook calendar as tentative appointment, so you will get a reminder for that request even if you forget to accept/reject the meeting request. Sometimes the time taken for different meeting requests will differ; this is because the sniffer runs only when MAPI is idle.

Now, let’s look at why few of the Meeting invites are not appearing on the calendar?

• The sniffer works only with the items in the outlook Inbox, so if you have moved the items from the Inbox even before sniffer acts on it then it will not appear. This can be through a rule.
• If you have set outlook to not process some items. Ensure that you have selected Process requests and responses on arrival and Process receipts on arrival(Tools -> Options -> Email Options -> Tracking Options)
• If a user mailbox configured in more than one machine and runs at the same time. Here only one can a sniffer (Sniff owner) at a time. You may use the /sniff parameter along with outlook command to set the current machine as Sniff owner. You may also use outlook /cleansniff to clear of the other sniff information.
• See if any other third party add-ins marking the item as sniffed. You can very well check the item property PR_PROCESSED using the tool MFCMAPI to verify it, if the value is set to true the outlook sniffer will not run on it.
• Is your outlook MAPI is busy always due to any third party add-ins or applications. Sniffer will only process when the MAPI is idle. You can try to disable the Add-ins to isolate the issue.
• Verify if the sniffer idle time is set to too long.
  HKEY_Current_User/Software/Microsoft/Office/11.0/Outlook/Options/General, check for the below DWORD.

         AutoProcessIdleTime – how much MAPI idle time is required before the Sniffer will act.
         AutoProcessIdleTimeMax – this says to wait for how long for the next try if the MAPI was not idle on the previous attempt.

Both the above values are specified in milliseconds, so the decimal value 1000 equal to 1 sec. If you want to adjust the value you can set 10 sec for AutoProcessIdleTime (default is 30 sec, i.e. 30000) and set 30 seconds for AutoProcessIdleTimeMax (default is 60 sec, i.e. 60000). If you set too low value that can reversely affect the outlook performance sometime.So if the above values are not present, create the DWORD as mentioned above and set the decimal value as 10000 and 30000 respectively.

• Based on the experience, the BlackBerry service usually processes the incoming meeting requests prior to the sniffer process, which may causes the meeting requests not to be saved to the Calendar folder automatically and tentatively. So disable the blackberry service to test and isolate the issue.

Do you feel tuff with Meeting Invites, don’t worry from Exchange 2007 and 2010 the calendar invites are processed by the Exchange Calendar Assistant. Hopefully you will not encounter any such problem.

Note – This article is not applicable for Exchange Server 2007 and above versions.

Cheers!
-Praveen