Outlook 2011 for Mac - version 14.2.4 (fully udpated) - on Lion. 
 
When I try to search for an email message using Spotlight, I get "No Results". Have tried the various solutions in this forum, none of which work. Specifically, tried to force a reindex by copying the identity into Spotlight Preferences - Privacy tab, so that I could then remove it. Got the following error message: "The item couldn't be added or removed because of an unknown error."

Not sure if this makes a difference but Outlook is tracking more than 2000 folders across 3 email accounts, and tens of thousands of messages. But my main Inbox is under 100 messages.
I have an odd problem searching in Outlook.  I have done the usual steps of rebuilding the database, forcing Spotlight to reindex, deleting the files in the library preferences that Microsoft recommends.  But I can't quite believe this is an indexing issue.

The problem I have is this. I want to search for all Outlook mails that fall in a specific date range.  I have found that all Outlook searches by "sent" or "date received" using a date criterion work only if the date provided is not a calendar date. in other words it finds all mails sent "this week", "this month" perfectly.  I can also use the "greater than" criterion and enter the number of days, and that works too. Thus it finds all mail sent more than 700 days ago also perfectly.  But when I ask it to fund all mails sent before or even on 05/01/2011 it does not work, and produces strange answers.

When I called into the IT help at my university, the tech person there (not a mac specialist) seemed to have the same problem.  Is there an issue with microsoft exchange servers with the latest iterations of office 2011?

Grateful for any help.

Mark