High CPU usage when typing a message in Outlook

Question

OS: Win 11 Pro

Office: 2016 Pro

Hi everyone,

CPU activity goes to 16-22% when typing a message in Outlook 2016 and returns to 1 % when typing stops.

Deactivating (all) add-ins and Graphic acceleration did not solve the issue.

Deactivating spell check options did not cure the problem either.

The problem seems to be specific to Win 11 and does not occur on Win 10 OS.

If anyone has any suggestion on how to solve this issue...
PDMC

***moved from Outlook / Windows / Classic Outlook for Windows / For business***

Answer 1

Does this issue also occur in Classic Outlook from the Office Pro Plus 2024 Retail version?

Answer 2

This issue will repro in the retail SKUs. It's not an issue that everyone will notice though. You can check if it's affecting you by opening Task Manager and open an email side by side and compare as you type. If you find it affecting your work, you can switch the retail SKU to Semi Annual channel using the registry key workaround in the Known Issue, CPU spikes when typing in classic Outlook for Windows - Microsoft Support.

Answer 3

This issue will repro in the retail SKUs. It's not an issue that everyone will notice though. You can check if it's affecting you by opening Task Manager and open an email side by side and compare as you type. If you find it affecting your work, you can switch the retail SKU to Semi Annual channel using the registry key workaround in the Known Issue, CPU spikes when typing in classic Outlook for Windows - Microsoft Support.

I can confirm it also happens in the retail version of Outlook 2024. My CPU goes up to 16-17% whenever I type in the message box.

I'm surprised this is an issue since November 2024 and nothing is done yet.

Answer 4

What's strange: The bug appears since version 2406 which was published in June 2024, but why did the CPU spikes during typing e-mails start around November 2024 and not already before? There seems to be a second condition which was not fulfilled before November?

Answer 5

I don't know it it's just a coincidence, but I currently also have massive GPU (not CPU) usage from Desktop Window Manager parallel to using Outlook. So now Outlook as well as DWM make my system very slow nearly always when I work something.

With the rollback to 2405 this bug was gone, but with SemiAnnual Channel (2408), it's there again: Outlook also causes high GPU (not CPU) load of about 30-60% by the task "Desktop Window Manager" when Outlook is visible and not overlapped by other windows. Often it helps to quit Outlook and to start it again, but sometimes, this has to be done even several times. This normally does not make the fan work, but it makes Outlook significantly slower all the time.

@Gabriel Bratton, could you maybe also reproduce this and report it to the right place at Microsoft?