Overview

• Microsoft has acknowledged a bug in classic Outlook that causes CPU usage to spike by 30-50% when users type emails.
• The issue impacts Outlook Version 2406 Build 17726.20126 and later on Current, Monthly Enterprise, and Insider update channels.
• As a temporary solution, Microsoft recommends switching to the Semi-Annual Channel, which is not affected by the bug.
• The problem, reported since November 2024, persists despite users attempting common troubleshooting steps like disabling spell-check and add-ins.
• Microsoft's engineering team is actively investigating the issue, but no permanent fix has been released yet.