The Imap4.exe process crashes intermittently on a Microsoft Exchange Server 2007 server. Additionally, the following event is generated in the Application log::
This issue occurs when IMAP4 clients perform a search on a mailbox that contains thousands of messages that use nonconsecutive the PR_INTERNET_ARTICLE_NUMBER property. In this scenario, the search operation generates a large query. Therefore, the stack overflows and causes the Imap4.exe process to crash.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.