Microsoft’s new Outlook for Windows took about 10 seconds to display a specific email after its Windows 11 notification was clicked, according to a side-by-side test by Windows Latest. Outlook Classic opened the corresponding message almost immediately. The result is one publication’s measurement on its own setup, not a universal benchmark across devices and accounts, but it highlights a user-visible delay in a basic workflow.
The tester found that application startup had improved enough for the two versions to feel close when launched directly. The notification route behaved differently. Clicking the banner caused new Outlook to open the full inbox before loading the intended message. Manually opening the application and selecting the new email took about five seconds in the same observation—half the notification path’s time.
The two products have different foundations. Outlook Classic is the established Win32 desktop client. New Outlook uses Microsoft Edge’s WebView2 runtime to deliver a web-based interface. Windows Latest attributes the notification sequence to several steps in that web layer, including resuming processes, authenticating, retrieving the thread and rendering it. That explanation is technically plausible, although the test does not isolate which step caused most of the measured delay.
Task Manager also showed ten processes for new Outlook, including WebView2 utility, GPU, manager and service-worker components, versus one compact Outlook Classic process. In the publication’s sessions, new Outlook used 490MB to 636MB of memory while idle and about 4% CPU. Classic used 117MB to 148MB and less than 1% CPU. Mailbox size and system state can change those numbers, so they are best treated as a reproducible observation to test elsewhere rather than fixed requirements.
Microsoft has acknowledged broader WebView2 performance concerns. The report says the company was testing a “Delayed Message Timing” API in late 2025 to diagnose slow behavior in WebView2 applications, though the publication found no evidence that it was being used for Outlook notification clicks.
New Outlook has continued to gain functions. Updates in 2026 improved folder search and shared-mailbox access, added automapped calendars and announced further work on a unified inbox, mail merge and PST imports. Microsoft also delayed a forced enterprise opt-out milestone from April 2026 to March 2027, according to the report, giving organizations more time with Classic.
The notification result shows why feature parity is only part of that transition. Opening the message a user just selected is a latency-sensitive action; a multi-second pause can make the newer client feel less responsive even when it eventually reaches the same content. A broader test across hardware, account types and network conditions would be needed to determine how common the 10-second delay is.
