How to search for item type in Outlook?

In the search box, include messageclass:IPM.Note to find only e-mail messages.

Here is the full list (as far as I know) of message classes for Outlook/Exchange 2010 items. I found some of this information in Mastering Microsoft Exchange Server 2010 by Jim McBee and David Elfassy. I found the rest by adding the "Message Class" column to an Outlook folder view and noting the values for different types of messages in that folder.

  • IPM.Activity: Item in Outlook Journal folder
  • IPM.Appointment: Item on Outlook Calendar
  • IPM.Contact: Item in Outlook Contacts folder
  • IPM.Document: Document/file (I don't believe this filter would ever yield results when searching Outlook e-mail)
  • IPM.Note: E-mail message
  • IPM.Note.Rules.OofTemplate.Microsoft: Received out-of-office auto reply e-mail
  • IPM.Note.SMIME: Encrypted or digitally signed e-mail message
  • IPM.Note.Microsoft.Conversation: Office Communication Server instant message or group chat session
  • IPM.Note.Microsoft.Conversation.Voice: Office Communication Server call
  • IPM.Note.Microsoft.Fax: Fax message
  • IPM.Note.Microsoft.Missed.Voice: Notice of missed Office Communication Server call
  • IPM.Post: Internet post item, usually for a public folder (I am unfamiliar with this one)
  • IPM.Post.RSS: RSS feed
  • IPM.Schedule: Meeting-related notice (will catch all of the specific types below)
  • IPM.Schedule.Meeting.Canceled: Meeting cancellation notice
  • IPM.Schedule.Meeting.Notification.Forward: Forwarded meeting invitation
  • IPM.Schedule.Meeting.Request: New or updated received meeting invitation
  • IPM.Schedule.Meeting.Resp.Neg: Sent declined meeting notice
  • IPM.Schedule.Meeting.Resp.Pos: Sent accepted meeting notice
  • IPM.Schedule.Meeting.Resp.Tent: Sent tentative meeting notice
  • IPM.StickyNote: Item in Outlook Notes folder
  • IPM.Task: Item in Outlook Tasks folder
  • IPM.Note.Microsoft.Voicemail: Voicemail left via Exchange 2007 Unified Messaging server or equivalent
  • IPM.Sharing: The Sharing Message Object Protocol is used to share mailbox folders between clients. This protocol extends the Message and Attachment Object Protocol.

You should use this:

[Message Class]:IPM.Note

instead of

messageclass:IPM.Note

Because this variant doesn't work in other localization (non-english).