Home Microsoft Acknowledges Outlook Classic Bug and Offers a Temporary Fix News Microsoft Acknowledges Outlook Classic Bug and Offers a Temporary Fix 3 min read Published: April 18, 2025 Key Takeaways Microsoft has acknowledged that there’s a bug in Outlook Classic that slows CPUs by 30-50%. The company has offered a temporary workaround by shifting to the Semi-Annual Channel. This issue is six months old, but Microsoft hasn’t offered a permanent fix so far. Microsoft has acknowledged a bug in its Outlook Classic software, which spikes CPU usage by 30%-50%. The problem has persisted since November 2024, with several users complaining of a slow system and an abnormal increase in CPU usage when they type emails. Users have reported that disabling spell-check and graphic acceleration also didn’t help. One user even said that the temperatures of their i9-14900HX CPU reached 95 degrees Celsius when they opened the ‘New Message’ tab. However, Microsoft didn’t offer a long-term fix for the problem. Only a stopgap fix. Users can switch to the Semi-Annual Channel, where this problem hasn’t been observed. The issue appears to be specific to the Current, Monthly Enterprise, or Insider channels. Here’s how you can do it as a home user: Open Command Prompt (ensure you’ve selected the ‘Run as administrator option’) Type the following command: reg add HKLM\Software\Policies\Microsoft\office\16.0\common\officeupdate /v updatebranch /t REG_SZ /d SemiAnnual Once you’ve added the registry key, select File > Office Account > Update Options > Update Now to switch. If you’re running an organization, Microsoft has published a detailed guide on how you can update the channel using Group Policy, Office Deployment Tool (ODT), Configuration Manager, Microsoft Intune Administrative Templates, and the admin center. Meanwhile, the company has said that the Outlook team is investigating the issue. Why No Fix? The problem has been around for more than six months now, and it’s quite odd that a tech behemoth like Microsoft has been sitting on it. Is the problem that complex, or is there something under the sheets? Well, it’s a known fact that Microsoft wants to do away with its Outlook Classic product and have users shift to the new Outlook for Windows. However, the company has gone on record to say that it will offer support for Classic until the end of 2029. Those two commitments don’t align well, do they? Users won’t ‘willingly’ shift to the new Outlook because it lacks some features offered by the Classic version. For instance, there are no multiple mail profiles, shared mailboxes, custom forms, or SharePoint calendar sync with the new Outlook. Microsoft Outlook Classic custom forms Plus, many features, such as offline support, the Notes module, and .PST support, are only partially available. So, why would users want to switch to an inferior product? Could it be possible that this whole ‘CPU-slowing bug’ thing is a strategy to push users to the new product? Well, these are just speculations, and we’ll never reach the bottom of this theory. It may be possible that Microsoft will release a permanent fix soon and put these theories to rest. For now, we’ll have to wait for the next development on this issue. Krishi is a seasoned tech journalist with over four years of experience writing about PC hardware, consumer technology, and artificial intelligence.  Clarity and accessibility are at the core of Krishi’s writing style. He believes technology writing should empower readers—not confuse them—and he’s committed to ensuring his content is always easy to understand without sacrificing accuracy or depth. Over the years, Krishi has contributed to some of the most reputable names in the industry, including Techopedia, TechRadar, and Tom’s Guide.  A man of many talents, Krishi has also proven his mettle as a crypto writer, tackling complex topics with both ease and zeal. His work spans various formats—from in-depth explainers and news coverage to feature pieces and buying guides.  Behind the scenes, Krishi operates from a dual-monitor setup (including a 29-inch LG UltraWide) that’s always buzzing with news feeds, technical documentation, and research notes, as well as the occasional gaming sessions that keep him fresh.  Krishi thrives on staying current, always ready to dive into the latest announcements, industry shifts, and their far-reaching impacts.  When he's not deep into research on the latest PC hardware news, Krishi would love to chat with you about day trading and the financial markets—oh! And cricket, as well. View all articles by Krishi Chowdhary Our editorial process The Tech Report editorial policy is centered on providing helpful, accurate content that offers real value to our readers. We only work with experienced writers who have specific knowledge in the topics they cover, including latest developments in technology, online privacy, cryptocurrencies, software, and more. Our editorial policy ensures that each topic is researched and curated by our in-house editors. We maintain rigorous journalistic standards, and every article is 100% written by real authors. More from News View all View all