Outlook Error When Opening PDF Attachments: The Memory Could Not Be Read

When opening a PDF attachment directly in Microsoft Outlook, you may encounter a Windows Application Error with the message: “The instruction at 0x[address] referenced memory at 0x[address]. The memory could not be read.” This error typically occurs due to a conflict between Adobe Acrobat (or Adobe Reader) and Outlook, and can usually be resolved by reinstalling Adobe Acrobat.

Symptoms

• Opening a PDF attachment directly from Outlook (right-click and Open, or double-click) triggers a Windows Application Error
• The error message states: “The instruction at [address] referenced memory at [address]. The memory could not be read. Click on OK to terminate the program.”
• Saving the PDF to the desktop or another folder and opening it from there works without any error
• The issue may affect all PDF attachments or only occur intermittently

Cause

This error is caused by a conflict between Microsoft Outlook and Adobe Acrobat (or Adobe Reader). When you open a PDF directly from an Outlook email, Outlook uses the default PDF handler to render the file within a temporary location. If Adobe Acrobat’s installation has become corrupted or its integration with Outlook is not functioning correctly, the application crashes with a memory read error.

The fact that saving the PDF first and opening it from the desktop works normally confirms the issue is specific to the Outlook-to-Adobe handoff, not the PDF file itself.

Resolution

Option 1: Reinstall Adobe Acrobat (Recommended)

Reinstalling Adobe Acrobat resolves the corrupted integration with Outlook and is the most reliable fix.

1. Close Outlook and any open Adobe Acrobat or Adobe Reader windows
2. Open Settings > Apps > Installed apps (or Control Panel > Programs and Features on older systems)
3. Find Adobe Acrobat (or Adobe Acrobat Reader) in the list and select Uninstall
4. Once the uninstall completes, download the latest version from Adobe’s website
5. Install Adobe Acrobat and restart the computer
6. Open Outlook and test opening a PDF attachment directly from an email

Option 2: Repair Adobe Acrobat

If you prefer not to uninstall, you can try repairing the installation first.

1. Open Adobe Acrobat (or Adobe Reader)
2. Go to Help > Repair Installation
3. Follow the prompts to complete the repair
4. Restart the computer and test again in Outlook

Option 3: Disable the Adobe Acrobat Outlook Add-in

If the error persists after reinstalling, disabling the Adobe add-in in Outlook can prevent the conflict.

1. In Outlook, go to File > Options > Add-ins
2. At the bottom, select COM Add-ins from the dropdown and click Go
3. Uncheck any Adobe-related add-ins (such as Adobe Acrobat Create PDF)
4. Click OK and restart Outlook

Workaround

While troubleshooting, you can work around the error by saving the PDF attachment to your desktop (or any local folder) before opening it. Right-click the attachment in Outlook, select Save As, choose a location, and then open the saved file. This bypasses the Outlook-to-Adobe handoff that causes the crash.

Key Takeaway

The “memory could not be read” error when opening PDF attachments in Outlook is almost always caused by a corrupted Adobe Acrobat installation. Reinstalling Adobe Acrobat is the quickest and most reliable fix. If you continue to experience the issue after reinstalling, try disabling the Adobe Outlook add-in or repairing the installation.

Related Resources

• Fix: Error Opening PDF Attachments in Outlook (Memory Could Not Be Read)
• Fix: Action Blocked When Opening Email Attachments in Outlook (Attack Surface Reduction)
• Fix: PDF Files Cannot Be Previewed in Outlook or Windows Explorer

If you need help resolving this issue on your workstations, get in touch with our team.