Microsoft's new Outlook adds 10‑second delay versus Outlook Classic
The latest Windows version of Outlook introduces a performance regression, with common tasks taking up to 10 seconds compared to the instant response of Outlook Classic, raising concerns about productivity and competitiveness.
Microsoft's new Outlook version on Windows introduces a performance regression, with common actions such as opening a mailbox or composing a message taking up to 10 seconds, whereas Outlook Classic completes them instantly [Windows Latest]. Users reported the slowdown immediately after the rollout, noting that navigation between folders and loading message previews are especially affected.
What shipped The regression appears across core email‑client functions—folder navigation, message composition, and search. Microsoft has not provided a cause or a fix timeline, and the company continues to push incremental updates to the new Outlook without a performance‑related patch announced yet [Windows Latest].
Why it matters A multi‑second lag erodes productivity for professionals who rely on Outlook for rapid communication, and it gives rival email clients a performance advantage. For Microsoft, the issue underscores the importance of rigorous performance testing before releasing major UI changes in enterprise‑focused software where speed is a key differentiator.
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