SharePoint Document Issues

How to Fix Cannot Save MP4 Attachment to SharePoint List Item

Chanuka Geekiyanage Sep 30, 2026 870 views

Question details

Users are unable to save an MP4 attachment to a SharePoint list item, encountering a catastrophic failure error despite the file being under the allowed size limit.

How to Resolve MP4 Attachment Saving Failures in SharePoint List Items

Product: Microsoft SharePoint
Device & OS: not provided
Scenario: Attaching an MP4 video file to a specific SharePoint list item.
Observed behavior: The system throws a 'Catastrophic failure' error and prevents the MP4 attachment from being saved, which typically indicates an underlying tenant configuration or service-side issue.

Before you start

Verify that your MP4 file size does not exceed the SharePoint list attachment limit and test uploading a different file type to check if the error is specific to video files.

Solution 1Recommended

Escalate to Microsoft 365 Support via Tenant Administrator

Since the 'Catastrophic failure' error often stems from deep tenant configuration or service-side issues, Microsoft's backend support team must investigate the environment.

This specific attachment failure is usually not resolvable from the end-user interface. It requires deep tenant-level administrative access and backend diagnostics from Microsoft.

Identify your Administrator

Contact your organization's IT department or the designated Microsoft 365 administrator who manages your company's tenant environment.

Access the Admin Center

Have the administrator log into the Microsoft 365 Admin Center using their admin credentials.

Create a Support Ticket

Navigate to 'Support' and then 'Help & support' in the left-hand menu to open a new service request.

Provide Detailed Information

Supply the support team with the URL of the affected SharePoint list, the exact MP4 file attempting to be uploaded, and a screenshot of the 'Catastrophic failure' error code for investigation.

Escalate to Microsoft 365 Support via Tenant Administrator

Workaround while waiting for support: While the support ticket is pending, consider uploading the MP4 file to a standard SharePoint Document Library and pasting the sharing link into a text field on your list item.

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Frequently Asked Questions

What is the maximum attachment size for a SharePoint list item?

By default, the maximum file attachment size for a SharePoint list item is 250 MB, though SharePoint administrators can adjust this limit up to 250 GB in the central administration settings depending on the server version.

Why does SharePoint block certain attachments?

SharePoint restricts certain file types (like .exe or .bat) to protect the environment from malicious software. While MP4 files are generally permitted, custom tenant security policies might inadvertently block or corrupt video uploads.

How can I share an MP4 file if the list attachment fails?

As a reliable workaround, upload your MP4 file to a SharePoint Document Library. Once uploaded, generate a sharing link for the video and paste that URL into a 'Hyperlink' or 'Multiple lines of text' column in your list item.

Document & File Issues