Outlook is an email client from Microsoft with various smart integrated features such as calendar, task management, contact management, add-ins, and many more.
Quite often, many users report that they are facing issues with Microsoft Outlook, whether it is the latest installation or an old one. Like any other application, Outlook also has some issues and bugs. While most are gone with the latest Outlook version, there are still many that have not received the required attention. One of the known common issues with Outlook is that Outlook shutting down unexpectedly sometimes.
There are various issues that can be encountered by any Outlook user while working or just after opening the application itself, such as Outlook has stopped working, crashing on startup, crashing in safe mode, Outlook not responding, Outlook crashing while sending emails or loading profile, and crashes because of rundll32 / olmapi32.dll / kernelbase.dll / wwlib.dll / ntdll.dll.
Though there could be many reasons why Outlook crashes on your PC, in this article, we will walk you through a couple of issues and the outright solutions to each, respectively.
Why does Outlook keep closing unexpectedly?
There are many reasons for this issue, and we have listed a few of the common ones below:
- Corruption of Outlook PST files.
- Virus or malware Infection
- Incorrect Windows registry file.
- Compatibility issues
- Crashes while trying to upgrade to the latest version.
- Too many Add-ins can cause Outlook to crash.
Method to resolve Outlook closes unexpectedly issue
The best proven solutions in 2026 to fix Outlook automatically closes after opening are:
Method 1. Check your Security Software
System Security tools and software like McAfee, Avast, Avira, etc., cause issues with Outlook due to specific settings you have set as per your preference or enabled by default.
Try disabling the security software/antivirus tool temporarily and check if it helps or not; in most of the cases, it turns out that the Security / Antivirus tool was the sole reason that caused the tool to stop working. If the issue is fixed, you can uninstall antivirus/security software.
Method 2. Disable Hardware Acceleration Functionality
Hardware acceleration is often used by most of the newest applications for Windows. To enhance the overall experience of Outlook, disabling the option of Hardware Acceleration available in the application would come to be a savior.
Follow the steps below to disable the hardware acceleration:
Step 1: Launch Outlook.
Step 2: Click on the File tab > click Options.
Step 3: Click Advanced, check Disable Hardware graphics acceleration, and click OK.
Step 4: For the change to take effect, close the application and start Outlook again.
Method 3. Try Opening Outlook in Safe Mode
If Outlook keeps shutting down unexpectedly, the first thing you should try is opening it in Safe Mode. This will disable all your add-ins and customizations.
To open Outlook in Safe Mode follow the below steps:
Step 1: Close Outlook if it is open.
Step 2: Press and hold the CTRL key on your keyboard, and then double-click the Outlook shortcut to launch it.
Step 3: Click Yes when prompted to start in Safe Mode.
Once Outlook is open in Safe Mode, test to see if the issue persists. If it does, then you know that one of your add-ins or customizations is causing the problem. Many users commonly report that the Kaspersky Anti-Spam add-on was causing the “Outlook closes unexpectedly” problem, and disabling it solved the issue for them.
Follow the steps below to disable Outlook Add-ins:
Step 1: Open Outlook.
Step 2: Click on the File tab, click Options.
Step 3: From the left pane, click on Add-ins. In the Window on the right-side, make sure COM Add-ins value is selected for Manage. Then, click Go.
Step 4: Deselect all the active Add-in and click OK.
Step 5: Now, close Outlook, restart it, and check if the issues are solved.
If Outlook starts normally, find the incompatible add-in and remove it.
Method 4. Reduce OST File Size
When I was looking for reasons for “Why is my Outlook shutting down unexpectedly”? My answer was a 45 GB OST file that was just too much for my Outlook to handle. As per Microsoft, modern Outlook supports OST files up to 50 GB. But several reports and user forums suggest otherwise. When your OST file size grows to 25 GB or larger, your Outlook will hang and may crash often. To fix Outlook keeps closing itself, I had to resolve the oversized OST file issue.
Method 5. Perform a Clean Startup of Windows
If Outlook closes unexpectedly, it may be because there are too many programs running in the background. To fix this, you can try performing a clean startup of Windows. This will disable all non-essential programs and services, which may be causing the problem. To do this, follow these steps:
Step 1: Press the Windows key + R to open the Run dialog box.
Step 2: Type msconfig and press Enter.
Step 3: In the System Configuration window, go to the Services tab and check the box next to Hide all Microsoft services. Click Disable all.
Step 4: Go to the Startup tab and click Open Task Manager.
Step 5: In the Task Manager window, for each item in the Startup tab, click the item and then click Disable.
Step 6: Close the Task Manager window.
Step 7: Click OK in the System Configuration window.
Step 8: Restart your computer and check if Outlook is still closing unexpectedly. If not, you can re-enable each program and service one by one to determine which one is causing the problem.
Method 6. Create a New Outlook Profile
Outlook profile corruption is another major reason why your Outlook is closing unexpectedly. To fix Outlook keeps closing itself, you must create a new Outlook profile with these steps:
Step 1: Go to Control Panel > Mail > Show Profiles.
Step 2: Select the current default profile and click Remove.
Step 3: Then, click the Add button and configure the new Outlook profile.
Note: Remember to make the new profile your default one by selecting the Always use this profile option.
Method 7. Uninstall Microsoft Office & install it again
If your Outlook installation is a part of Microsoft’s Office suite and you face crashing issues or encounter Outlook has stopped working message, uninstalling Office & reinstalling it might solve the issue. Doing this has helped many users follow the steps below:
Step 1: Go to Control Panel, and click on Programs and Features.
Step 2: Select Microsoft Office, right-click, and click Uninstall.
Step 3: Once Office uninstallation is complete, install it again and check if the issue still exists.
Method 8. Repair Corrupt OST or PST File
Corruption in the Outlook data file, be it OST or PST, can cause Outlook to crash unexpectedly. To resolve the issue, you must repair the data files. To repair OST file, follow these steps:
Step 1: Go to the location where your OST file is. Select it and delete it.
Step 2: Open Outlook. It will connect to Exchange and automatically build a new healthy OST file.
If you are still facing the crash issue, then check if your Outlook profile has a PST file added and repair it. To repair corrupt PST, use ScanPST.exe. However, the free tool can only fix minor inconsistency issues. If the native tool fails, then use a professional Outlook PST repair tool.
Author's verdict
Hopefully, one of these solutions worked for you in fixing the “Outlook closes unexpectedly” problem. If not, then you need to use the advanced diagnostic troubleshooter for deep analysis.
In most cases, the native methods will be able to resolve the problem. But, if PST corruption is the culprit, I recommend using the Kernel for Outlook PST Repair, as running the ScanPST.exe repeatedly may cause permanent data loss.
Frequently asked questions
Q: Will deleting the OST file delete my emails?
A: No. OST is basically an offline copy of your mailbox on the Exchange Server. When you delete it, the original data stays safe on the server.
Q: How to increase the size of the OST file?
A: The most reliable way to configure the OST or PST file size is to use the Windows Registry settings.
Q: I checked the Event Viewer and found "Olmapi32.dll". Is it related to the “Outlook closes unexpectedly” problem?
A: Yes. The Olmapi32.dll is a core file in Microsoft Outlook that mainly handles your email, calendar, and contact data. Errors related to this .dll file can lead to Outlook’s abrupt exits. To fix Outlook automatically closes after opening issue, disable any recently installed add-in or try to repair the Office 365 installation.
