What To Do When Microsoft Outlook Won't Open

Different things can cause this problem, but there are several fixes to try

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When you select the Microsoft Outlook program from the Start menu or a shortcut icon, but Outlook won't open, the proper fix depends on what you experience and the version of Microsoft Outlook that you're using.

Reasons Why You Can't Start Outlook

Several issues could cause Outlook to open incorrectly or not at all. Some common culprits include:

  • Problematic add-ins or extensions.
  • Damaged files.
  • A corrupted profile.
  • Navigation pane issues.

There are other issues, too, that can contribute. Maybe you've added a new program to your computer that doesn't get along with Outlook, for example, or your system has a virus. Regardless of the specific cause, there are several key troubleshooting fixes to try that might help.

How To Fix Outlook Not Opening in Windows

If you use Outlook on a Windows computer and Outlook doesn't open or opens with problems, try these troubleshooting steps in the order presented here, from simple to more complicated.

If you use the cloud-based Microsoft 365 on a PC or a Mac, the automated Support and Recovery Assistant tool can diagnose and fix many issues, including the problem of Microsoft Outlook not starting.

  1. Open Outlook in Safe Mode. If Outlook opens as expected in Safe Mode, the issue is likely an add-in or toolbar extension.

  2. Disable add-ins. One or more add-ins could be conflicting with Outlook and cause the problem. Disable all add-ins and see if this resolves the issue.

    1. Select File > Options > Add-ins.
    2. In the Manage section, select Go.
    3. Clear the check boxes next to the add-ins you want to disable.
    4. Select OK.
  3. Scan your system for viruses, Trojans, spyware, and other malware. If you find a problem, resolve it with your security software, reboot your computer and try restarting Outlook again.

  4. Repair Outlook. The Outlook application may be damaged. Use the built-in Microsoft 365 repair utility to fix it.

    1. Close all Office applications.
    2. Go to Start > Control Panel.
    3. Select Category View.
    4. In the Programs section, select Uninstall a Program.
    5. Right-click Microsoft 365 and choose Change.
    6. Select Online Repair or Repair. Choose Yes if a user account control prompt appears.
    7. Restart Outlook after the process completes.
  5. Repair your Outlook profile. Outlook profiles can become corrupted, causing all sorts of problems, including Outlook not opening.

    1. Select File > Account Settings > Account Settings.
    2. Go to the Email tab.
    3. Choose Repair to open the Repair wizard (this option is not available for Outlook Exchange accounts).
    4. Follow the prompts to complete the wizard and restart Outlook.
  6. Repair Outlook data files. If Outlook still doesn't open, use the Inbox Repair tool to find and possibly fix the problem.

    1. Exit Outlook.
    2. Download and open the Inbox Repair tool from Microsoft.
    3. Select Browse and navigate to your personal folders (.pst) file, then select Start.
    4. Choose Repair if the scan finds errors.
    5. When the repair is complete, restart Outlook.
  7. Reset the navigation pane. A startup issue with the navigation pane can prevent Outlook from opening correctly. Resetting the navigation pane might resolve the issue.

    1. Exit Outlook.
    2. Go to Start Run or press Windows Key+R.
    3. Type or paste outlook.exe /resetnavpane and select OK.
    4. Open Outlook. The navigation pane will be reset.

How To Fix Outlook Not Opening in Mac

The following troubleshooting techniques apply to Outlook 2016 for Mac and Outlook 2011 for Mac.

  1. Check for updates. A recent update could include a fix for the problem of not being able to start Outlook. Check for and install any available updates, even if you cannot open Outlook.

    1. Select Help > Check for Updates.
    2. Choose Update to download and install all available updates.
  2. Rebuild the Outlook database. Using the Microsoft utility to rebuild a corrupted database might solve the problem of Outlook not opening on a Mac.

    If you have a Microsoft Exchange account, rebuilding the database deletes any information that isn't synced with the server. Back up any Outlook data stored only on your computer before you rebuild the database.

    1. Exit all Office applications.
    2. Press the Option key and select the Outlook icon in the Dock to open the Microsoft Database Utility.
    3. Select the identity of the database you want to rebuild.
    4. Choose Rebuild.
    5. When the process is complete, restart Outlook.
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