Microsoft has recently acknowledged a performance issue in the classic version of Outlook for Windows, where users experience significant CPU usage spikes while typing emails. This problem, first reported in November 2024, has led to system slowdowns and overheating concerns for many users.
The issue manifests as CPU utilization increasing by 30% to 50% during email composition, with some users reporting temperatures reaching up to 95 degrees Celsius. This problem is associated with Outlook Version 2406 Build 17726.20126 and later, released in June 2024, affecting users on the Current Channel, Monthly Enterprise Channel, and Insider channels.
While Microsoft investigates a permanent solution, they recommend switching to the Semi-Annual Channel, where the issue has not been observed. Organizations can refer to the "Change the Microsoft 365 Apps update channel for devices in your organization" guide for instructions. Home users can add a registry key to switch update channels by following these steps:
- Open Command Prompt as an administrator.
- Enter the following command:
reg add HKLM\Software\Policies\Microsoft\office\16.0\common\officeupdate /v updatebranch /t REG_SZ /d SemiAnnual - In Outlook, navigate to File > Office Account > Update Options > Update Now to apply the change.
Microsoft is actively working on a fix and will provide updates as they become available. Users are encouraged to monitor official Microsoft support channels for the latest information.
Source: TechSpot Microsoft confirms Outlook Classic bug that causes CPU spikes while typing, offers workaround
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