Outlook won't Open

Question

The outlook app on my computer will not open no matter what I have tried. I've tried restarting my computer, uninstalling everything and reinstalling, clearing data, and just about everything I can think of that would fix the problem. Does anyone know what is happening here and how I can fix it? Really need this app to work for my job and it has been costing me lots of valuable time troubleshooting.

Answer 1

If Outlook is not opening, there are several troubleshooting steps you can take to resolve the issue:

1. Check Compatibility Mode: Sometimes, Outlook may be set to run in compatibility mode, which can cause issues. To disable compatibility mode:
   • Locate Outlook.exe in the installation directory (commonly found in C:\Program Files\Microsoft Office\OfficeXX where XX corresponds to your version).
   • Right-click on Outlook.exe and select Properties.
   • Go to the Compatibility tab and ensure that the Run this program in compatibility mode for option is unchecked.
   • Click OK to apply the changes.
2. Repair Office: You can try repairing the Office installation:
   • Go to Control Panel > Programs > Uninstall a program.
   • Select Microsoft 365 and click Change.
   • Choose Quick Repair and follow the prompts. If that doesn't work, you can try the Online Repair option.
3. Registry Edit: If the problem persists, you may need to modify the registry. Be cautious with this step:
   • Exit Outlook.
   • Open the Registry Editor by typing regedit in the Run dialog (Win + R).
   • Navigate to HKEY_CURRENT_USER\Software\Microsoft\Office\<x.0>\Common\Internet\ (replace <x.0> with your Office version, e.g., 16.0 for Office 2016).
   • Find the UseOnlineContent value and set it to 2.
4. Check for Updates: Ensure that your Office and Windows are up to date, as updates can fix bugs and improve performance.
5. Safe Mode: Try starting Outlook in safe mode to see if it opens. You can do this by holding the Ctrl key while launching Outlook.

If none of these steps resolve the issue, consider reaching out to Microsoft support for further assistance.

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References:

• Outlook is unable to start in Windows 7 or 8
• Repair process for an Office Click-to-Run application does not start

Answer 2

I had the same problem and the answer on this page worked!!

https://learn.microsoft.com/en-us/answers/questions/5651275/outlook-(new)-365-suddenly-will-not-open

Answer 3

Hi @Lockinger, Brayden,

Thank you for posting your question in the Microsoft Q&A forum.

I can understand how stressful it is when Outlook won’t open and you need it for work. The new Outlook for Windows relies on web components and cached app data, when those break (often after an update), the app can silently fail to launch even though classic Outlook or Outlook on the web still work.

To troubleshoot this more effectively, could you please clarify this:

When you click the new Outlook icon, do you see nothing at all (no window), or a blank/white window that never loads?

While we're waiting for your response to the question above, here are a few steps that you can try on the time:

1/ Make sure Outlook isn’t stuck in the background:

• Press Ctrl+Shift+Esc to open Task Manager and end any Microsoft Outlook/Outlook (New)/Calendar/OneAuth processes, then try launching Outlook again

Microsoft’s troubleshooting page starts here with a restart/uninstall/reinstall workflow for the new Outlook.

Reference: Troubleshoot Outlook for Windows issues

2/ Repair or Reset the “Outlook (New)” app:

• Settings > Apps > Installed apps > Outlook > Advanced options > Repair. If it still won’t open, run Reset (this removes local cache, you’ll sign in again)
  

3/ Rebuild local Outlook cache that commonly blocks startup:

• Close Outlook. In File Explorer paste and delete/rename these folders (they’ll be rebuilt):

%localappdata%\Microsoft\Olk

%localappdata%\Microsoft\OneAuth

Then restart Windows and open Outlook again.

4/ Repair (or reinstall) Microsoft Edge WebView2 runtime:

• The new Outlook uses WebView2 to render its UI. If WebView2 is missing/corrupted, Outlook may not open at all.
• Download the Evergreen Standalone WebView2 installer from Microsoft and Run as administrator, then launch Outlook.

You can follow the instructions here: New Outlook refuses to open

5/ Fix broken sign‑in components (WAM/AAD Broker Plugin):

• If you get a blank sign‑in pane or Outlook never authenticates, the Web Account Manager (WAM) plug‑ins may be broken (often by security software). Microsoft explains symptoms and remediation here.

6/ Run SaRA (Support and Recovery Assistant)

• Download and run the Microsoft Support and Recovery Assistant to auto‑diagnose Outlook launch/auth issues.
• You can download it here.

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.   

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.

I look forward to continuing the conversation.

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