Microsoft Knowledge Base Article 900930 contains the following introduction:
This article discusses the availability of the Update for Windows XP (KB900930).
Install this update to address multiple Microsoft Outlook Express 6.0 issues in Microsoft Windows XP. This update addresses an issue in which messages are incorrectly handled if the Subject line in an e-mail message contains the word "begin." This update also addresses a display issue about threads that are marked as "watched" in newsgroups. Additionally, this update addresses two issues in which Outlook Express stops responding.