Classic Outlook users are reporting frequent crashes starting from March 12, 2026. When you launch the app, it fails immediately and asks to restart in Safe Mode. Microsoft is tracking this under incident EX1254044 and has confirmed it stems from a conflict between older Outlook builds and a recent Teams Meeting Add-in update.

Classic Outlook crashes and prompts to start in Safe Mode. Exception code: 0xc0000005

Technical Analysis

The crash is an access violation (0xc0000005) triggered when Classic Outlook loads the Microsoft Teams Meeting Add-in. Older builds of Office (2016 and later on the Click-to-Run channel) are incompatible with a recent version of the add-in. When Outlook attempts to initialize the add-in, the version mismatch causes a memory access violation and the application terminates.

Administrators checking the Application Log in Event Viewer will typically see Event ID 1000 with details including:

  • Exception code: 0xc0000005
  • Faulting application: OUTLOOK.EXE
  • Faulting application path: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE

The specific faulting module may vary by Office version. Common culprits include MSVCP140.dll and MsoAria.dll.

This is similar to other memory access errors, like when users need to fix Outlook error 0xc0000409.

How to Fix Outlook Crash 0xc0000005

Since this is a version conflict, you need to either disable the add-in or force an update to a compatible Office build.

Note: Microsoft has confirmed this issue and is working on pushing updated builds to affected users. This content will be updated as new information arrives.

Step 1: Disable the Teams Meeting Add-in

If Outlook will not stay open long enough to change settings, use Safe Mode to disable the add-in:

  1. Hold the Ctrl key and click your Outlook shortcut.
  2. Select Yes when prompted to start in Safe Mode.
  3. Go to File > Options > Add-ins.
  4. At the bottom, ensure COM Add-ins is selected in the Manage box and click Go.
  5. Uncheck Microsoft Teams Meeting Add-in for Microsoft Office.
  6. Click OK and restart Outlook normally.

Step 2: Update Office via Word

Updating Outlook directly is difficult if the app keeps crashing. Use another Office application to pull the latest updates:

  1. Open Microsoft Word.
  2. Go to File > Account.
  3. Select Update Options > Update Now.
  4. Wait for the update to finish, then launch Outlook.

Step 3: Perform an Online Repair

If the update does not resolve the conflict, repairing the Office installation resets DLL registrations and resolves version mismatches:

  1. Right-click the Start button and select Installed Apps.
  2. Find your Microsoft Office or Microsoft 365 installation in the list.
  3. Click the three dots and select Modify.
  4. Select Online Repair and follow the prompts.

For organizations managing many endpoints, deploying updates via PowerShell scripts or configuration management tools works best across the network. You can also find broader operating system solutions in our Windows fixes section.

Need hands-on help? Contact our team.

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