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Can't open Outlook; error reads EXC_BAD_INSTRUCTION

Patte K 0 Reputation points
2026-01-06T17:58:39.5333333+00:00

Got a new Mac last week and transferred all data. All was working fine until this morning when Outlook crashed and won't let me open. I've tried every tip on Apple site and Microsoft site. Keep getting error EXC_BAD_INSTRUCTION. I've deleted, with help from my work IT and an Apple agent, to uninstall and re-install multiple times from multiple ways. Word, Excel, etc are working fine. I am also able to access Outlook directly from the Microsoft site and use on my iPad (2nd generation) and iPhone XR. Outlook is tied to my Office 365 account, but we even tried to download outside of 365 and that didn't work either.

Thanks!

Outlook | MacOS | New Outlook for Mac | For business
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  1. Hani-Ng 11,155 Reputation points Microsoft External Staff Moderator
    2026-01-07T01:40:42.5333333+00:00

    Hi Patte K

    Thank you for reaching out to Microsoft Q&A forum.

    According to the details you provided specifically that you recently migrated data to a new Mac and that the EXC_BAD_INSTRUCTION happens immediately upon launch. It is highly likely that an old, incompatible setting or plugin was transferred from your previous device.

    Since standard uninstalling and creating a new profile did not work, I would like to share some information from my side that I hope will be helpful to you. These seem like they are designed to address compatibility conflicts between your new Mac's processor and the migrated data.

    Here are some recommended solutions you can try:

    Run Outlook in Compatibility Mode

    Your new Mac likely uses an Apple Silicon with M-series chip. If the migration moved an old plugin, Outlook would shut down immediately as a result. Forcing Outlook to run in "Rosetta" mode fixes this.

    • Make sure Outlook is closed > Open Finder > Applications
    • Right-click (or Control-click) on Microsoft Outlook and choose Get Info.
    • Check the box labeled Open using Rosetta > Close the window and try to open Outlook.

    Force Outlook to Open without Add-ins

    You can use the Terminal to force Outlook to launch while ignoring any third-party plugins that might be causing the crash.

    • Press Command + Space to open Spotlight, type Terminal, and press Enter.
    • Copy and paste the following command and press Enter:
      open -n /Applications/Microsoft\ Outlook.app --args -DisableAddins
    • If Outlook opens: This confirms a plugin is the cause. While Outlook is open, go to remove any old items.

    Remove Container Files Standard uninstalling often leaves behind the data files that contain the corruption.

    • Click Finder > On the menu bar, click Go > Go to Folder...
    • Paste this path: ~/Library/Containers
    • Find the folder named Microsoft Outlook > Move it to the trash
    • Restart your Mac and open Outlook.

    If the above does not work, you should reset the specific Office data connections.

    • Repeat the "Go to Folder" step above, but paste this path: ~/Library/Group Containers/UBF8T346G9.Office
    • Look for a sub-folder named Outlook and move only the Outlook sub-folder to the Desktop (we move it to the desktop as a backup instead of deleting it, just in case).
    • Try to launch Outlook.

     Validate Fonts

    • Press Command + Space on your keyboard to open Spotlight > Type Font Book and press Enter.
    • Click All Fonts in the left menu > Press Command + A to select all fonts > Right-click and choose Validate.
    • If any fonts have a Red X, delete them and restart Outlook.

    Please try these solutions and let me know the outcome. Additionally, could you please share the macOS version you are running so I can better understand your situation?

    I look forward to your response.

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  2. Patte K 0 Reputation points
    2026-01-06T18:07:38.71+00:00

    All of these require being able to access Outlook which I can't. It shuts down too fast to be able to be able to open. Where do you find System Preferences > Spotlight > Privacy on the Mac. Where do you find Microsoft Database Utility on the Mac. Neither came up with a Spotlight search.

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  3. AI answer

    2026-01-06T17:58:52.3033333+00:00

    The error message EXC_BAD_INSTRUCTION typically indicates that there is an issue with the application trying to execute a command that is not valid. Since you have already tried uninstalling and reinstalling Outlook multiple times and other Office applications like Word and Excel are functioning properly, the issue may be related to the underlying file system or specific settings in your Outlook profile.

    Here are a couple of suggestions to try:

    1. Check for Case-Sensitivity: If your file system is formatted as case-sensitive, it might cause issues with Outlook. You can check this using Disk Utility. If it is case-sensitive, you may need to rename certain framework files as needed (for example, renaming OsfCore.framework to osfcore.framework).
    2. Check Outlook Profiles: If you have multiple Outlook profiles, ensure that the correct one is set as default. You can manage this through the Outlook Profile Manager.
    3. Delete Other Profiles: If you have other profiles that you do not use, consider deleting them to avoid conflicts. This can be done through the Outlook Profile Manager or the Microsoft Database Utility.
    4. Exclude Profiles from Spotlight Indexing: Sometimes, Spotlight indexing can interfere with Outlook. You can exclude your Outlook profiles from Spotlight indexing through System Preferences > Spotlight > Privacy.

    If these steps do not resolve the issue, you might need to consult with Microsoft Support for more advanced troubleshooting specific to your installation and setup.

    References:

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