Issue with WOPI Document Editing – Formatting Problems

Question

Hi,

We are using WOPI in our legal case management system to enable document editing. Recently, we’ve encountered an issue where, in edit mode, text inside tables appears in white, and in some cases the table width becomes very small.

This problem occurs only in edit mode—documents display perfectly in read-only mode. We also tested the same document in OneDrive and observed the same behavior. However, when the document is downloaded and opened locally, it works as expected.

We’re unsure what’s causing this issue. Could you please help us identify the root cause and advise on how to fix it?

For your reference, I have attached the image.

Thanks,

Jayrag

Answer 1

The described behavior points to a Word for the web / Microsoft 365 for the web rendering issue rather than a WOPI host bug or a problem with the document itself, since:

• Read-only mode renders correctly.
• The same issue appears when opening from OneDrive.
• Downloaded documents open correctly in the desktop Word client.

From the available information, the most relevant guidance is to treat this as a Microsoft 365 for the web issue and follow the standard troubleshooting and escalation path for WOPI integrations:

1. Run the WOPI Validator
   • Use the WOPI Validator against the integration and confirm that all tests pass. This is a prerequisite before escalating any Microsoft 365 for the web issue.
   • If any tests fail, correct those issues first, as they can cause unexpected behavior in editing scenarios.
2. Check common and known issues
   • Review the “Common implementation problems” and “Known Issues integrating with Microsoft 365 for the web” for anything matching the scenario (for example, cookie or loading problems that might affect how the editor initializes styles or layout).
   • Specifically verify that:
     • Third-party cookies are allowed or *.officeapps.live.com is in the browser’s cookie allow list, as missing authentication cookies can cause Microsoft 365 for the web to fail to load correctly in an iframe, which may manifest as broken or partial rendering.
3. Confirm whether the issue is document-format related
   • If the affected files are legacy binary formats (.doc, .xls, .ppt), ensure that the integration is using the documented conversion flow to modern formats (.docx, .xlsx, .pptx) before editing.
   • Microsoft 365 for the web does not edit binary formats directly; it converts them via the convert action and PutRelativeFile. If the host is not handling conversion correctly, the editor may be working on an unexpected or partially converted file, which can cause layout anomalies.
4. Narrow down scope and collect diagnostics
   • Test with:
     • A simple new .docx created directly in Word for the web.
     • A copy of the problematic document with all custom styles removed.
   • If the issue reproduces only with certain documents or styles, capture:
     • The exact file(s) involved.
     • Screenshots of read-only vs edit mode.
     • Browser type and version.
     • Whether the file is binary or already in a modern format.
5. Engage Microsoft with full WOPI troubleshooting data
   • After confirming that the WOPI Validator passes and that the issue is not due to a known configuration problem, follow the troubleshooting guidance to work with Microsoft engineers:
     • Provide validator results.
     • Provide network traces and WOPI logs around the editing session.
     • Reference that the issue reproduces in OneDrive and only in edit mode, and that the desktop client renders correctly.

Given the constraints of the available information, the most practical next steps are:

• Validate the WOPI implementation with the WOPI Validator.
• Ensure third-party cookies / *.officeapps.live.com are allowed.
• Confirm proper handling of legacy-to-modern format conversion.
• If the problem persists, escalate through the Microsoft 365 for the web troubleshooting channel with the collected diagnostics.

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References:

• Known Issues
• Troubleshooting interactions with Microsoft 365 for the web
• Edit legacy binary document formats