New Outlook Issues

Dear Alfonzo,

Good day, and I appreciate the detailed description of your issue. I understand that you are experiencing an unexpected issue with New Outlook. As a forum moderator, I am not able to access your account or step into the backend systems to diagnose and resolve this for you. My role here is limited to providing general guidance and solutions that you can apply from your side.

From your description, since Outlook on the web works fine, this points more toward a local New Outlook client / WebView2 / cached app state issue, rather than a mailbox or Exchange service issue. I also tried to replicate the behavior in my test environment but was not able to reproduce it. For your reference, here is the version I am running:

Microsoft Outlook Version: 1.2026.609.400

Client Version: 20260619010.12

WebView2 Version: 149.0.4022.98 (Stable)

Please try the following steps to see if they help:

1.Repair New Outlook

• Close Outlook completely.
• Go to Windows Settings > Apps > Installed apps > Search for Outlook
• Select the three dots > Advanced options.
• Choose Repair first, then Reset if needed.
• Restart your computer after the repair completes.

2.Clear New Outlook local cache

If Repair / Reset does not work, close Outlook completely from Task Manager, then rename the following folders (this forces New Outlook to rebuild its local cache and authentication data). Press Windows + R and run:

• %localappdata%\Microsoft\Olk > rename to Olk.old
• %localappdata%\Microsoft\OneAuth > rename to OneAuth.old

Then reopen New Outlook and sign in again.

3.Reinstall WebView2

New Outlook depends on WebView2 to render much of the desktop client experience, so a WebView2 issue can cause UI freezing or message/calendar panes not responding. 

Press Windows + R and run:

C:\Program Files (x86)\Microsoft\EdgeWebView\Application\150.0.4078.42\Installer

Note: This is the version folder that matches your case. If you see a slightly different version number, just open the folder that looks similar.

Right-click the Installer folder and select Open in Terminal.

Next, enter the following command:

.\setup.exe --uninstall --msedgewebview --system-level --verbose-logging --force-uninstall

Press Enter

Once uninstalled, reinstall WebView2 from the official page:

Microsoft Edge WebView2 | Microsoft Edge Developer

Look for the Evergreen Standalone Installer and select x64 (for most modern PCs).

Right-click the downloaded file and select Run as Administrator.

4.Contact Microsoft support

If the issue persists after the steps above, I recommend that the Global Admin in your organization create a service request with Microsoft Support. A technical support engineer can perform a remote session to investigate the situation, verify the backend configurations, and run any necessary synchronization tools to resolve the problem. If the issue requires further attention, they can escalate it to a specialized team for deeper analysis. For detailed instructions on how to get support, please refer to Get support - Microsoft 365 admin. If you don't know who your IT administrator is, please refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support 

I hope this information is helpful. Please follow these steps and let me know how it goes. If you have any questions or need further assistance, please feel free to share them in the comments so I can continue to support you. Thank you for your patience and understanding. I'm looking forward to your reply.

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Per this other thread:
https://techcommunity.microsoft.com/discussions/OutlookGeneral/new-outlook-calendar-view-cannot-open-modal-dialogs-e-g-new-eventsettings-%E2%80%93-mail/4532652

Forcing an update to the newest version fixed this issue for me.

olk --force-update

Hi Alfonzo,

This is a known local cache and WebView2 environment breakdown tied directly to the 1.2026.617.600 update. Since the web app works flawlessly, your cloud mailbox is completely fine — the local desktop app client is strictly at fault.

Execute these aggressive troubleshooting steps immediately to force a resolution:

FORCE AN APP RESET: Complete kill Outlook via Task Manager. Open Windows Settings > Apps > Installed Apps. Locate Outlook (New), click the three dots, select Advanced Options, and click Repair. If that fails, click Reset.

WIPE THE LOCAL CORRUPTED CACHE: Open the Run dialog (Win + R), paste %localappdata%\Microsoft, and press Enter. Locate the Olk and OneAuth folders. Delete them entirely or rename them to http://Olk.old and http://OneAuth.old. This forces Outlook to rebuild its configuration data from scratch upon the next launch.

REINSTALL WEBVIEW2 RUNTIME: New Outlook is completely reliant on Microsoft Edge WebView2 to render the user interface. A bad component update will break UI actions like closing, minimizing, or switching panes. Download and run the WebView2 Evergreen Standalone Installer directly from the official Microsoft Developer portal to patch the core rendering engine.