Basically, Microsoft removed the proper manual Exchange dialog — but we can bring it back.

Here’s how to force Outlook Classic to actually show the old manual setup wizard instead of the Microsoft 365 autodiscover flow.

🧩 Option 1: Force legacy account setup via registry

Step 1 — Close Outlook

Make sure Outlook and all Office apps are fully closed (check Task Manager too).

Step 2 — Add the “Disable Office 365 Autodiscover” keys

1. Press Win + R, type regedit, and hit Enter.

2. Navigate to:

   HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover
   

   (Use 15.0 for Office 2013, 14.0 for Office 2010.)

3. Add these DWORD (32-bit) entries and set each to 1:

   ExcludeHttpsRootDomain
   ExcludeHttpsAutoDiscoverDomain
   ExcludeSrvRecord
   ExcludeLastKnownGoodUrl
   ExcludeExplicitO365Endpoint
   

4. (Optional but helps) add:

   DisableOffice365SimplifiedAccountCreation
   

   under
   HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\setup
   value = 1

These stop Outlook from hijacking you into the Microsoft 365 flow.

Step 3 — Restart Outlook’s Mail profile tool

Open Control Panel → Mail (Microsoft Outlook) → Show Profiles → Add.

Now when you choose “Manual setup or additional server types”, you’ll actually get the legacy Exchange dialog (with “Server” and “User Name” fields).

From there, follow the classic Exchange manual setup:

• Server = mail.yourdomain.com

• User = your alias or email

• More Settings → Connection → Exchange Proxy Settings → enter your RPC/HTTPS details.

🧩 Option 2: Use “Mail” Control-Panel tool directly (skip Outlook entirely)

1. Press Win + R, type

   control /name Microsoft.Mail
   

   and hit Enter.

2. Click Email Accounts → New → Manual setup or additional server types → Microsoft Exchange Server or compatible service.

That route completely avoids the Modern Auth wizard and still exists in Office 2021/365 builds as long as you’ve set the registry keys above.

🧩 Option 3: Install an older “MSI” Office build

If you’re on Click-to-Run (subscription) and nothing works, you can install the perpetual Office 2016 MSI or Office 2019 LTSC version — they still support true manual setup by default.
(You can keep your current licence key; you just need the MSI installer ISO.)

⚙️ Bonus: quick .reg file you can save and double-click

Copy the following into Notepad and save as FixOutlookManualSetup.reg, then double-click it:

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover]
"ExcludeHttpsRootDomain"=dword:00000001
"ExcludeHttpsAutoDiscoverDomain"=dword:00000001
"ExcludeSrvRecord"=dword:00000001
"ExcludeLastKnownGoodUrl"=dword:00000001
"ExcludeExplicitO365Endpoint"=dword:00000001

[HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\setup]
"DisableOffice365SimplifiedAccountCreation"=dword:00000001

Once imported, reopen the Mail control-panel applet → Add Profile → manual setup — and you’ll finally get a password prompt for your own Exchange server instead of being railroaded into Microsoft 365.