Microsoft Confirms High CPU Usage Bug in Outlook Classic

Processor Usage Bug Identified in OutlookMicrosoft has officially acknowledged a longstanding issue affecting Outlook Classic users, characterized by an unexpected surge in processor usage. This software glitch has been a point of frustration for many, but the company has now provided an interim solution.Details of the Outlook CPU BugThe CPU usage problem in Outlook is not a new phenomenon. First brought to light in November 2024, this bug has persisted for some time. According to Microsoft‘s documentation, users might witness a 30% to 50% spike in CPU usage while composing emails in the Windows variant of Outlook Classic. Some reports even mention Intel Core i9-14900HX processors reaching temperatures above 95 degrees Celsius merely by opening the ‘New Message’ window.Current Status and Interim SolutionsThe root cause of this issue remains unidentified. Nevertheless, it appears to be prevalent in certain versions, such as the Current Channel, Monthly Enterprise Channel, and Insider Channel versions, especially those that include Version 2406 Build 17726.20126, which was released in June 2024, and later updates. While a permanent solution has not yet been rolled out, Microsoft suggests a temporary workaround. Users encountering these performance challenges can switch the update channel of their Microsoft 365 apps to the more stable Semi-Annual version. Meanwhile, the Microsoft Outlook team is actively working to resolve the issue.