Solved: Outlook for Mac Crashing on Launch in 2026

Ritu Roy | fix how to mac os olm outlook for mac | 7 minutes read | Modified on: 15-01-2026

This article explains multiple ways to resolve the issue of Microsoft Outlook for Mac crashing on Launch. It also covers the common causes behind the problem and shares tips to help prevent it from happening again. If you are currently experiencing this issue, make sure to read the article carefully and follow the solutions outlined below.

Important: Before attempting any fixes, back up any unsent emails or draft messages by copying them into a text file or another external application. This step helps prevent accidental data loss during troubleshooting.

Method 1: Restart Microsoft Outlook and macOS

Restarting Outlook can often resolve minor or temporary glitches by refreshing background processes.
Completely close Microsoft Outlook (ensure it is not still active in the Dock).
Wait for about 60 seconds to allow all related processes to stop.
Launch Outlook again and verify whether the issue has been resolved.
If Outlook continues to crash, restart your Mac by clicking the Apple menu and selecting Restart.

Method 2: Keep Outlook, macOS, and Microsoft Office Updated

Running outdated software is one of the most common reasons Outlook for Mac crashes on startup. Updating all related components can often resolve compatibility issues.

Update Outlook and Microsoft Office

Open Microsoft Outlook.
From the top menu, click Help and then choose Check for Updates.
Download and install any available updates.
Restart Outlook once the update process finishes.

Update macOS

Click the Apple menu and open System Settings.
Go to General and select Software Update.
Install the latest macOS updates and restart your Mac.

Method 3: Launch Outlook in Safe Mode

Safe Mode runs Outlook without add-ins or custom configurations, making it easier to identify the source of crashes.

Close Outlook completely.
Press and hold the Option key while clicking the Outlook icon in the Dock
Keep holding the key until Outlook opens.
Observe whether Outlook works normally in Safe Mode.
If it does, the issue likely lies with add-ins or user settings.

Method 4: Disable Outlook Add-ins

Third-party add-ins can sometimes conflict with Outlook and cause it to crash during launch.

Open Outlook (use Safe Mode if needed).
Go to Tools and select Manage Add-ins.
Disable all add-ins.
Restart Outlook normally.
Re-enable add-ins one at a time, restarting Outlook after each to identify the faulty one.
Leave the problematic add-in disabled or check for an updated version from the developer.

Method 5: Clear Outlook Cache Files

An overloaded or corrupted cache can negatively affect Outlook’s performance.

Read More – How to Clear Outlook Cache Files

Quit Microsoft Outlook.
Open Finder and press Command + Shift + G.
Paste the following path and click Go:
~/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook Preferences/
Move cache-related files to a backup folder on your Desktop.
Reopen Outlook to allow it to rebuild the cache.

Method 6: Reset Outlook Preference Files

Damaged preference files may cause Outlook to behave unexpectedly.

Close Outlook.
Open Finder and press Command + Shift + G.
Enter ~/Library/Preferences/ and click Go.
Locate files starting with com.microsoft.outlook and move them to a backup folder.
Restart Outlook to generate fresh preference files.

Method 7: Repair the Outlook Database

A corrupted database is a frequent cause of Outlook crashes.

Close Outlook.
Open Applications, then select Microsoft Outlook.
Launch Microsoft Database Utility.
Choose the main identity and click Rebuild.
Wait for the process to complete (this may take time for large mailboxes).
Restart Outlook.

Method 8: Create a New Outlook Profile

If the existing profile is damaged, creating a new Outlook Profile can resolve the issue.

Open System Settings.
Navigate to Control Center and select Microsoft Outlook Profile Manager.
Select the + icon to set up a new profile.
Set the new profile as the default.
Open Outlook and add your email accounts again.

Note: Ensure a stable internet connection, as emails may need to be re-downloaded.

Method 9: Reduce Mailbox Size

Large mailboxes can strain Outlook and lead to frequent crashes.

Read Also – Reduce Mailbox Size in Outlook

Open Outlook.
Go to File and select Archive.
Move older emails to a local folder and export them as an .olm file.
Try to keep the mailbox size under 10 GB.
Restart Outlook.

Method 10: Scan for Malware

Malware infections can interfere with Outlook’s normal operation.

Install a trusted antivirus tool (such as Malwarebytes for Mac).
Run a full system scan.
Remove any detected threats.
Restart your Mac and open Outlook again.

Method 11: Check Network Stability

Unstable internet connections can cause syncing problems and crashes.

Test your internet by opening websites or streaming a video.
Restart your router or switch to a wired connection if needed.
In Outlook, go to Send/Receive and enable Work Offline, then switch back online once the connection stabilizes.

Method 12: Resolve Font Conflicts

Corrupt or incompatible fonts can trigger Outlook crashes.

Open Font Book using Spotlight search.
Select all fonts, then click File > Validate Fonts.
Disable or remove fonts marked with warnings.
Restart Outlook.

Method 13: Monitor System Resources

Insufficient system resources can also lead to crashes.

Open Activity Monitor via Spotlight.
Check Memory, CPU, and Disk usage.
Close unnecessary applications.
Keep at least 10% of disk space free.
If resource usage remains high, consider upgrading RAM or storage.

Method 14: Reinstall Microsoft Outlook

Reinstalling Outlook provides a fresh installation and can resolve persistent issues.

Quit Outlook.
Open Applications and drag Outlook to the Trash.
Empty the Trash.
Download the latest Outlook version from the Microsoft website or the Mac App Store.
Install Outlook and reconfigure your email accounts.

Method 15: Reset Keychain Access

Corrupted Keychain entries may interfere with Outlook authentication.

Open Keychain Access using Spotlight.
Open Preferences and choose the option to Reset My Default Keychain
Re-enter your email credentials in Outlook.
Restart Outlook.

Method 16: Test with a New macOS User Account

System-level issues may affect Outlook performance.

Open System Settings > Users & Groups.
Create a new user account with administrator privileges.
Log in to the new account and set up Outlook.
If Outlook works properly, migrate your data or repair the original account using Disk Utility.

Method 17: Run Disk Utility

Disk errors can cause applications to crash unexpectedly.

Open Disk Utility via Spotlight.
Select your startup disk.
Click First Aid and run the scan.
Repair detected errors, restart your Mac, and launch Outlook again.

Common Reasons Why Outlook for Mac Crashes on Launch

Outlook may crash for several technical reasons, including:

Corrupted Outlook Profile: Damaged profiles can cause instability.
Outdated Software: Older versions of Outlook, macOS, or Office may not be compatible.
Large Mailbox or Cache Files: Excessive data can overload Outlook.
Faulty Add-ins: Third-party add-ins may conflict with Outlook.
Damaged Database: Sudden shutdowns can corrupt Outlook’s database.
Low System Resources: Insufficient memory, storage, or CPU power.
Malware Infections: Harmful software can disrupt Outlook processes.
Corrupt Preferences or Settings: Incorrect or damaged configuration files.

Prevent Outlook Crashes in the Future

Following a few best practices can help keep Microsoft Outlook running smoothly and reduce the chances of unexpected crashes.

Keep Software Up to Date

Keeping your software up to date ensures you benefit from the latest bug fixes and performance enhancements.

Check for updates monthly and install the latest versions of Outlook, Microsoft Office, and macOS.

Control Mailbox Growth

Oversized mailboxes can slow down Outlook and cause instability.

Back up older emails to local folders or export them as .olm files.
Aim to keep your mailbox size below 10 GB for optimal performance.

Back Up Emails Regularly

Frequent backups ensure your data stays safe even if Outlook encounters issues.

Export emails by navigating to File > Export.
Store backups on an external drive or secure cloud services like OneDrive or iCloud.

Minimize Add-ins

Only use add-ins that are necessary and trusted.

Avoid installing unverified extensions.
Keep all add-ins updated to maintain compatibility with Outlook.

Monitor System Performance

A healthy system helps Outlook run efficiently.

Use Activity Monitor to track memory, CPU, and disk usage.
Maintain at least 10% free disk space by removing unnecessary files.

Run Antivirus Checks

Malware can interfere with Outlook’s operation.

Run a comprehensive system scan at least once every month to ensure your device remains malware-free.
Use reliable antivirus software and keep virus definitions up to date.

Maintain a Stable Network

Email syncing relies on consistent internet connectivity.

Use a secure, high-speed internet connection.
Avoid unstable networks when sending or receiving large volumes of email.

Backup Tip: Cloud backups are convenient, but should always be protected with strong security measures such as two-factor authentication. Local backups remain offline and secure, but should be refreshed weekly to stay current.

Identify and Address Specific Crash Scenarios

Understanding when Outlook crashes can help you apply the right fix more quickly.

Start Outlook in Safe Mode, disable add-ins, rebuild the database, or reset preferences.
Clear cache files, reduce mailbox size, or stabilize your internet connection.
Try opening the attachment in another application to check for corruption.
Monitor system resources, close background applications, and resolve font conflicts.
Review Keychain Access entries or verify SMTP settings under Preferences > Accounts.

If the issue persists despite troubleshooting, contact Microsoft Support or consult a certified Mac technician for advanced diagnostics such as log reviews or hardware checks.

Helpful Resources

Microsoft Support: Visit support.microsoft.com for official Outlook troubleshooting guides and live assistance.
User Communities: Platforms like Reddit’s r/Office365 or the Microsoft Community forums offer real-world solutions from other users.
Crash Log Analysis: Use Console (search via Spotlight) to review Outlook crash logs and identify specific error codes.

Conclusion

Outlook for Mac crashing on Launch can be frustrating and disruptive, but the solutions discussed in this guide can help resolve most issues effectively. Consistent maintenance, regular updates, and routine backups are essential to prevent future crashes, especially during launch.

For reliable and flexible Outlook data backups, tools like MacArmy OLM Converter for Mac & Windows can be useful. This application allows you to export and save .olm files in multiple formats, including PST, EML, PDF, MSG, Yahoo Mail, Office 365, and more, ensuring your data remains accessible and secure.