Summary
- Microsoft’s fix for high CPU usage in Outlook expected in early May 2025.
- Disabling features or add-ins hasn’t helped mitigate the CPU spike issue.
- Users may revert to a previous Outlook version (2405) as a temporary solution but there may be security risks.
Your CPU should be flared up by intensive tasks, not by sending emails. But this is precisely what has been happening for a few Outlook users. Thankfully, though, Microsoft has finally put out a fix for this.
Microsoft has confirmed it is working on a fix for a persistent issue causing significant CPU usage spikes for users of the classic Outlook app on Windows. Those affected by the bug complain that they are experiencing CPU utilization jumping to between 30% and 50% while composing messages—this would, of course, depend on what CPU you have and how powerful it is, but the fact that it’s doing a significant jump at all is unintended behavior in itself. This not only impacts system performance but also leads to increased power consumption, and if you have a laptop, increased power consumption can lead to overheating and worsened battery life. So it’s a huge problem.
Initial troubleshooting attempts by users, such as disabling spell-checking features or third-party add-ins, haven’t really had any noticeable impact on the issue. Thankfully, though, Microsoft officially acknowledged the bug last week. In an update to its support documentation, the company specified that the issue is now confirmed to impact users subscribed to the Semi-Annual Channel who have updated their classic Outlook client to Version 2406 (Build 17726.20126) or any future builds.
While there’s not a live fix just yet, Microsoft has provided an estimated timeline for the rollout of the fix across its various update channels. Users in the Beta Channel can expect the fix first, around early May 2025. Following that, the fix is targeted for the Current Channel Preview by mid-May. Finally, the broader rollout to everyone else is planned with the same update rolling out around late May. So everyone will be getting the fix promptly, but it still has to make its way down the Insider channel pipeline—probably to ensure that the fix is actually good and works properly. It’s not the only issue Outlook has suffered from in the past few months—Microsoft has actually been on a bad streak with this app recently.
Related
If the issue really can’t take until May for you, the company suggests reverting the Outlook installation to a previous version, specifically Version 2405 (build number might vary depending on the specific release channel). Microsoft cautions against this approach as a long-term solution, as there have been a few security updates since this version, but it works in a pinch. If you have a laptop, for one, and you’re seeing degraded performance, you might want to put your PC’s own battery life before some security fixes temporarily. When the fixed new version is released, you can just grab that one.
Keep an eye out for an update next month if you’re suffering from this issue.
Source: Bleeping Computer