Classic Outlook clings to stale search results as Microsoft works on a fix

Microsoft’s Classic Outlook search defect can leave moved or updated emails visible in stale search results, creating user frustration, error messages, and avoidable productivity loss across affected mailboxes. The workaround requires a registry-based change that disables server-assisted search and reverts users to Windows Desktop Search, underscoring the operational risk of relying on a legacy client as Microsoft continues to push enterprises toward New Outlook and planned default migrations beginning in 2027.