Outlook Classic: Again forced update to New Outlook app

[German]I have again received a reader's report that Microsoft is probably currently switching installations of Outlook Classic to the new Outlook app again. Users of Microsoft Outlook 2000 have now been affected, as I have heard.

Old topic with the forced upgrade

Since 2023, I have published a whole series of blog posts dealing with the forced upgrade from Outlook Classic to the new Outlook app. In February 2025, Microsoft forced Windows 10 users who use the Mail and Calendar app to switch to the new Outlook app (I mentioned this in the post Windows 10 gets new Outlook app with preview update Jan. 2025 and update Feb. 2025).

And in January 2025, I reminded German administrators in corporate environments in the German article Erinnerung: Migration auf neue Outlook-App beginnt für einige Kunden that Redmond is again planning forced migrations from Outlook Classic to the new Outlook app.

• Microsoft 365 Business Standard and Premium license: Their users will be migrated from Outlook Classic to the new Outlook app from January 2025.
• Microsoft 365 Enterprise license: Their users will not be switched from Outlook Classic to the new Outlook app until April 2026 (see Migration to new Outlook app for enterprise user in April 2026.

But there are users who have purchased Outlook Classic as part of a Microsoft Office 2016, 2019, 2021 and 2024 purchase license. Here it was actually clear to me that there should be no forced upgrade.

Customers with Outlook has been auto-switched

On March 12, 2025, Sebastian contacted us by e-mail and reported that he had "the same effect with two of his customers that Microsoft now wants to abolish the COM-based desktop Outlook with a crowbar".

Outlook Classic switch – Click to zoom

A banner now states that Microsoft recommends using the new Outlook for Windows – and the button to change the mode is displayed in the title bar. It also says (translated) "If you skip this now, you will be redirected to the new experience the next time you start using Outlook". The banner also shows a Switch now button.

At this point, I stopped trying to understand the banner, because if I skip something, it means that I don't want to change. How I then automatically "get the new experience" at the next start is beyond me. The reader wrote: "Customer 1 says he is not aware of anything and the other just knows what Outlook is" and asks: "Is something up?"

I then asked which Office subscription the customers have and was told that they have Office 2000 licenses. So they are not subscription versions.

I had explained in various blog posts (e.g Windows 10 users are being forced to use the new Outlook app) why you should stay away from the new Outlook app. And there was also the German article Wechsel auf neue Outlook-App verhindern – noch eine Lösung, as well as the article Prevent migration from Classic Outlook to New Outlook  – how to take countermeasures.

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