How to Fix MS Outlook 2019 Won’t Open in Windows OS?

Microsoft Outlook 2019 is a highly resourceful email client that is widely used to manage emails, contacts, etc. At times, the users while trying to run the Outlook program from the shortcut icon or Start menu can’t open Outlook 2019. If you are one such user and looking for solutions to fix Outlook 2019 won’t open in Windows OS, then you’ve landed on the right page. In this post, we’ll be discussing all the possible solutions to fix this issue.

How to Fix the MS Outlook won’t Open Issue?

Here are some effective fixes to resolve the Outlook won’t open problem in Windows OS:

  1. Run Outlook in Safe Mode

One of the first things you should do when Microsoft Outlook 2019 won’t open, is launch Outlook in safe mode. This is because, in safe mode, Outlook opens without the add-ins. If the cause behind the problem is an incompatible add-in, then Outlook will run properly in safe mode.

To run Outlook in safe mode, follow these steps:

  1. Press Windows + R keys to launch Run.
  2. In the Run input field, type Outlook /safe and press ENTER.

If you are able to open Outlook in safe mode, then you can identify the problem-causing add-in and disable or remove it from the application. To do this, follow these steps:

  1. Go to File > Option > Add-ins.
  2. In the Manage section of Add-ins menu, ensure COM Add-ins option is selected. Then click GO. A new window will open in which all the installed add-ins will be listed.
  3. Unselect the suspicious add-ins. You can also remove them by clicking Remove instead of disabling them.
  4. Click OK and restart Outlook.
  5. Recreate OST File

If you are using Microsoft Exchange with Outlook and have Cached Exchange Mode enabled, it means there is an offline cache file on your system. This cache file or mailbox file is called Offline Storable Table (OST). Recreating this file may fix the problem of Outlook 2019 won’t open. To do so, follow these steps:

  1. Go to Windows Control Panel.
  2. Find and open Mail (Microsoft Outlook) (32-bit).
  3. In the Mail Setup window that opens, click Data Files.
  4. Select your Exchange email account and click Open File Location. Outlook will open the folder where the OST file is saved.
  5. Delete the OST file and open Outlook. The application will recreate the OST automatically by downloading the mailbox data from Exchange Server.
  6. Reset Outlook’s Navigation Pane

If you have made any changes to the navigation pane in Outlook 2019, then they might be causing the Outlook 2019 won’t open issue. You can reset the navigation pane by following these steps:

  1. Close Outlook.
  2. Press Windows + R keys to launch the Run
  3. In the Run input field, type exe /resetnavpane.
  4. Press ENTER.
  5. Create a New Outlook Profile

A corrupt Outlook profile can also prevent Outlook 2019 from opening. You can delete your current profile and create a new one to fix the issue. To create a new profile, follow these steps:

  1. Go to Windows Control Panel > Mail.
  2. In the Mail Setup window that opens, click Show Profiles.
  3. Click the Add
  4. Provide the required details – email address, name, password, etc.
  5. Click Finish.

Now, select the new profile from the profile menu and set it as the default profile.

  1. Ensure Compatibility Mode is Disabled

Microsoft Windows offers compatibility mode to run old applications that cause compatibility issues on Windows 10. If compatibility mode is enabled, you may face issues in opening the Outlook application. You can disable this mode to fix the issue by following these steps:

  1. Locate Outlook application’s shortcut (it’s usually on the desktop).
  2. Right-click Outlook shortcut. In the menu that opens, select Properties.
  3. Open the Compatibility tab and ensure that Run this program in compatibility mode option isn’t selected.
  4. Click Apply and then OK.
  5. Repair Outlook Data File

Sometimes, Outlook 2019 won’t open because of corrupt Outlook data file (PST). You can repair the PST by using Inbox Repair Tool (ScanPST.exe). This simple but highly useful utility is stored in Outlook’s installation folder.

ScanPST can easily remove minor corruption from Outlook data files. In case the corruption level is high, you need to use an advanced PST repair tool, such as Stellar Repair for Outlook.


If your Outlook 2019 is not opening in Windows OS, you can easily fix the issue by applying the simple solutions discussed in this post. For fast resolution, it is advised that you spend some time in identifying the root cause first and then apply the appropriate fix to resolve the Outlook won’t open issue.

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