Microsoft Outlook faces search errors and upcoming migration

Microsoft has confirmed a technical issue affecting the Server Assisted Search function in the classic desktop version of Outlook. When mailboxes are operated in online mode and users restrict searches to the ‘Current Folder’, the search results may fail to update correctly after actions are taken.

Specifically, messages that have been moved to different folders may still appear in the search results of the original folder. The error also affects changes to read status and category assignments, where the search display may not reflect the updated state. Attempting to open these outdated search results can lead to error messages.

Separately, Microsoft is planning a migration to the new Outlook starting in 2027. This transition highlights technical differences between versions: the new Outlook for Windows supports only server-side rules that run on the Exchange Server, whereas the classic version supports both server-side and client-side rules. Administrators are advised to review filter rules, as client-side rules require the desktop application to be active, and certain features like importing and exporting rule sets via .rwz files are currently only available in the classic version.