Recently a new bug that was confirmed by Microsoft which impact to Classic Outlook client performance when end user writing an email in Classic Outlook for Windows. As the user may notice the CPU consumption spikes dramatically whenever their typing in Classic Outlook client, even when the user switching to a different input software this still the case refer to below my test screenshots.
As per confirmed that this issue can occur after updating the Classic Outlook for Windows to Version 2406 Build 17726.20126+ on Current Channel, Monthly Enterprise Channel, or the Insider Channels.
Workaround
So far as Microsoft Outlook product team still investigating this issue, the only workaround for this issue is to switch to “Semi Annual Channel” where the issue has not been observed.
There are two methods available to switching to “Semi Annual Channel”:
- Using Office Deployment Tool —> the complicate way
- Using a registry command —> the easier way
As using the “Office Deployment Tool” will be more complicate for just switching to a different channel, hence I’ll only demonstrate the easier way to do a channel switching by using a registry command.
Using a registry command
1.Press “Windows logo key + X” to open the Quick Link menu > select “Terminal (admin)”.
2. Click Yes (or entering admin account & pw) if you saw the User Account Control prompt.
3. Paste the following command into the Terminal “reg add HKLM\Software\Policies\Microsoft\office\16.0\common\officeupdate /v updatebranch /t REG_SZ /d SemiAnnual” > then press Enter key.
4. After you added above registry key then > open a Office365 product (in my case the Excel program) > select File > Account > Update Options > Update Now.
Others
As the Outlook product team still investigating this issue you may following this discussion thread for more information :
Or following the MS support article for further update regarding this issue:
CPU spikes when typing in classic Outlook for Windows – Microsoft Support
