When using the online preview function in Office, some text may not be displayed, but it will appear correctly when downloaded to your local computer.

Question

I'm currently encountering a problem. I'm working on adjusting the font in a Word preview, setting it to a small 4 font size and a SimSun font. However, when I use the API to generate the document locally, it works fine. But when I deploy it to the test environment and preview it in the browser, some text is not displayed, even though the content is actually there. I copy and paste the content, and it appears there. Downloading the document from the preview page and opening it locally works fine.

Answer 1

Hi yu xiao

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

Based on your description, this behavior is expected and is related to how Word Online (browser preview) renders documents compared to the desktop Word client.

Word Online uses a server‑side rendering engine that does not fully match the local Word application. When very small font sizes (such as 4 pt) are used, especially with fonts like SimSun, some characters may not render visibly in the browser preview even though the content is still present in the document. This is why the text can be selected or copied, and why it appears correctly after downloading and opening the file locally.

Since the document displays correctly when opened in the desktop Word app, this confirms that the document content itself is not corrupted and that the issue is limited to the online preview experience.

As a general recommendation, if accurate visual rendering is required in the browser, consider avoiding extremely small font sizes or relying on fonts that are known to render consistently in Word Online. For scenarios where exact layout fidelity is critical, downloading and opening the document locally remains the most reliable approach.

Please note that this is a user-to-user support forum. Moderators, contributors including external Microsoft employees cannot directly intervene in Microsoft product features or access back-end systems. Our role is limited to providing technical guidance on reported issues, requests, or ideas.

Given these limitations, the most appropriate avenue for product changes or feature requests is to submit feedback through the official Microsoft feedback channel.

---

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

Answer 2

It seems that the issue you are experiencing with the online preview function in Office, where some text does not display correctly, may be related to font rendering in the browser. When using specific fonts like SimSun and very small font sizes, the online preview might not render them as expected, even though they appear correctly when downloaded and opened locally. This can happen due to limitations or differences in how fonts are handled in the web environment compared to local applications.

To troubleshoot this issue, you might consider the following steps:

1. Check Browser Compatibility: Ensure that the browser you are using for the online preview supports the font you are trying to use. Different browsers may have varying support for certain fonts.
2. Font Availability: Make sure that the font is available in the environment where the online preview is being rendered. If the font is not installed or accessible, it may not display correctly.
3. Adjust Font Size: Since you are using a very small font size (4), try increasing it to see if that resolves the visibility issue in the preview.
4. Test with Different Fonts: If possible, test with other fonts to see if the issue is specific to SimSun or if it affects other fonts as well.
5. Clear Browser Cache: Sometimes, clearing the browser cache can resolve rendering issues.

If the problem persists, it may be beneficial to report this behavior to Microsoft support for further assistance, as it could be a specific issue with the Office Online rendering engine.

---

References:

• Display issues in Office client applications