How to get rid of new tool bar saying: Try the new Outlook.

It works like a charm the first time!
Thank you for this solution.

P.S. Beware of creating a DWORD (a.k.a 32-bits), not a QWORD (aka. 64 bits)

You're talking about the button in my screenshot? It's not a toolbar but you can hide it using a registry key -
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\General
On right side blank space, click "New"DWORD 32: paste this line as the Dword 32 HideNewOutlookToggle

Right click the new made value, click "Change: Set last value 0x0000000(0) to 0x0000000(1) .... Done
Value: 1

Worked for me, so Thanks

"do now is to install a reputable free third-party email client like eMClient" is limited on the free version or "Mozilla's Thunderbird." is extremely limited on free. your better off should you choose to get either one is to pay in order to get more functionality of these programs

Hello, how can we remove the button to the new outlook interface on Outlook Express Version 16005.14326.21798.0 ? In registry i can't found HKEY_CURRENT_USER\Software\Microsoft\Office

But i see :

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Outlook Express

HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Outlook Express

and when i enter a Dword32 with the name HideNewOutlookToggle and value 1 this don't work...

Hi Cédric primes :

What is your Windows operating system?

Are you sure you mean Outlook Express, and not the Mail and Calendar UWP (Microsoft Store) app built in to Win 10 / Win 11? I have a Win 10 OS and Settings | Apps | Apps and Features shows I currently have Mail and Calendar v16005.14326.21798.0. Note that I don't use the built-in Mail and Calendar app; I use use the Outlook 2019 program included with my Microsoft Office 2019 suite as my email client.

The Wikipedia article Outlook Express notes that Outlook Express was discontinued several years ago and dates back to the Win XP era on computers with Internet Explorer 3.x through 7.x. Outlook Express was replaced several years ago by Windows Mail in Windows Vista.

If you have a Win 10 or Win 11 OS OS and use the built-in Mail and Calendar app (i.e., not the Microsoft Outlook program that comes with paid versions of Microsoft 365 and Microsoft Office 2016 / 2019 / 2021) then Diane Poremsky's suggested registry edit to remove the "Try the new Outlook" switch won't work and there's little you can do now to stop the forced migration to the "new" Outlook PWA (Progressive Web App) - see the June 2023 How-To Geek article The New Outlook for Windows Will Arrive for Everyone in 2024 and July 2023 BleepingComputer article Microsoft Force-Migrating Windows Mail & Calendar Apps to Outlook App in August.

If you currently use the Mail and Calendar app and don't want to be forced to use the "new" Outlook PWA (and don't want to pay for an email client like the Microsoft Outlook program included with Microsoft 365 and "perpetual" editions of Microsoft Office 2016 / 2019 / 2021) then you can use a reputable free third-party email client like eM Client or Mozilla's Thunderbird.

Dell Inspiron 5584 * 64-bit Win 10 Pro v22H2 build 19045.3930 * Firefox v122.0.0 * Microsoft Defender v4.18.23110.3-1.1.23110.2 * Malwarebytes Premium v4.6.8.311-1.0.2249 * Macrium Reflect Free v8.0.7783 * Microsoft Office Home and Business Version 2401 / Build 17231.20194 Click-to-Run