Summary: If you’ve been experiencing unexpected increases in CPU usage and other issues while using classic Microsoft Outlook, this is due to a confirmed bug in the email client. Microsoft is investigating the matter, but in the meantime, they have suggested that affected users switch to the Microsoft 365 Apps update channel.
Since November, reports have emerged of Outlook Classic users facing CPU spikes, freezes, and slow performance when composing messages.
Recently, Microsoft confirmed the issue in a published support document. The document mentions that CPU usage can spike as much as 30% or even 50% while writing emails in Outlook Classic for Windows. According to Tom’s Hardware, one user with an i9-14900HX reported their CPU temperature reaching a concerning 95 degrees when the New Message window was open.
Microsoft indicates that this issue can arise following an update to Version 2406 Build 17726.20126+ released in June 2024 across the Current Channel, Monthly Enterprise Channel, or Insider channels.
Currently, there is no fix available for this issue. As the Outlook Team continues their investigation, Microsoft advises users to transition to the Semi-Annual Channel release, where the problem has not been noted.
Organizations can refer to the “Change the Microsoft 365 Apps update channel for devices in your organization” guide for instructions on how to change update channels.
For individual users, a quicker alternative is to add a key to the Windows Registry by following these steps:
1. Open a Command Prompt window (make sure to select Run as administrator).
2. Enter the following command and hit Enter:
reg add HKLM\Software\Policies\Microsoft\office\16.0\common\officeupdate /v updatebranch /t REG_SZ /d SemiAnnual
3. After adding the registry key, go to Outlook and select File > Office Account > Update Options > Update Now to switch to the Semi-Annual Channel.
In other news from Microsoft, last week revealed reports that the company is nearing the launch of Recall. This controversial feature is intended to capture screenshots of user activities on a Copilot+ PC. It has faced delays due to security concerns, but a preview version is being made available to Insiders in the Release Preview Channel for Windows 11, version 24H2.
