Win forms app using old .NET FastReport version generates DOCX file, my word 2508 opens and messes up the tables

Question

Win forms app using old .NET FastReport version generates DOCX file, my word 2508 opens and messes up the tables

Marin Grabovac 0

When a Windows Forms application uses an older, non-updatable version of FastReport (.NET 2.0 Extension) to generate a DOCX file, a "matrix-like" structure is created that merges tables, causing them to overflow off the page. This issue occurs specifically when the file is opened in Word build version 2508, whereas it displays normally in Word build version 2507. The problem appears to be caused by PageBreaks generated within this matrix structure, which Word build version 2508 fails to interpret correctly. Although a programmatic solution to delete the PageBreaks was attempted, it resulted in the tables merging together and overflowing horizontally, indicating a deeper formatting issue related to how the Word interprets the DOCX file.

Example version 2508 is the picture that overflows: User's image

Example version 2507 is the picture that works well:
User's image

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Answer 1

Anonymous

Hi @Marin Grabovac,

Thank you for posting your question on Microsoft Q&A Community and for the detailed explanation and screenshots comparing Word build versions 2507 and 2508. To better understand and isolate the issue with the DOCX file generated by your Windows Forms app using FastReport .NET 2.0, here are a few clarifying questions:

1/ Does the issue occur only in Word build 2508?

Have you tested the same DOCX file in other builds (e.g., 2507, 2506)? If so, how do they behave?

2/ Is the DOCX file using a matrix-style layout with merged cells across rows/columns?

Are PageBreaks inserted programmatically or by FastReport’s export settings?

3/ Are you using any custom export configurations (e.g., matrix layout, page breaks, table width constraints)?

Is the DOCX generated with embedded styles or external templates?

4/ Is the DOCX opened locally or from a network/cloud location (e.g., OneDrive, SharePoint)?

Are there any differences in rendering when opened on different machines or OS versions?

5/ Have you tried removing PageBreaks manually or via script (e.g., Open XML SDK or PowerShell)?

Have you tested exporting to RTF or PDF and converting to DOCX afterward?

Once we have this information, I’ll be better equipped to suggest a targeted workaround or script-based solution.

Looking forward to your response.

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Marin Grabovac 0 Reputation points

2025-09-12T09:19:00.53+00:00
Does the issue occur only in Word build 2508?

Yes, the specific horizontal overflow and unreadable DOCX errors (on merging/joining split matrix tables) appear only in Word build 2508 and later. When tested on earlier builds (e.g., 2507 or 2506), the same DOCX file does not produce the overflow or "unreadable content" error; older versions handle the joining/gapping of large matrix tables with fewer layout problems.

Matrix-style layout and PageBreak handling

Yes, the DOCX file is generated from FastReport using a matrix-style (MatrixBased) layout, which heavily merges cells across both rows and columns.

PageBreaks are inserted programmatically by FastReport’s export engine to segment very large tables into multiple <w:tbl> blocks. After export, my scripts also remove these PageBreaks to reduce gaps.

Custom export configurations

Yes, the DOCX export uses custom FastReport settings: Matrix (pivot) layout with merged cells
Explicit/automatic PageBreaks between tables No additional table width constraints beyond the FastReport template The DOCX is generated **with embedded styles** from the report designer; no external templates are used.

Local vs. network and rendering

The DOCX is opened and edited locally (not from OneDrive, SharePoint, etc.).

No substantive differences are seen between Windows 10/11 or different machines, as long as the Word build is the same.

The problem starts only with Word 2508+—older Word versions on the same file do not show the overflow/corruption.

Manual/scripted PageBreak removal and other exports

Yes, scripts (C#, Open XML SDK) are used after export to remove <w:br w:type="page"/> and empty paragraphs in an attempt to visually join matrix segments.

Manual deletion of PageBreaks (in XML or Word UI) yields the same problem—overflows or unreadable documents if splitting/merging is not handled carefully.

Exporting to RTF or PDF and converting to DOCX does not fully fix the matrix split/merge problem:

RTF round-trip often breaks advanced cell merging (has some additional XML elements that are not RTF standard elementes and isn't readable by the Word)

PDF-to-DOCX conversion loses much of the table structure/layout, it works in some sort of manner, if I use online tool, but programaticaly overflowing issue occures

Summary:
This has escalated into a critical business issue affecting thousands of our end-users. A significant portion of our user base has upgraded to the newer Word versions (2508+) and is experiencing document corruption when opening our automatically-generated reports. These documents contain mission-critical data that cannot be compromised or recreated.
The root cause is tied to changes in Word's table rendering engine in version 2508 and later. When our system programmatically removes paragraph breaks between segmented matrix tables to create a seamless visual flow, Word's new merge algorithm triggers horizontal overflow errors, making the documents completely unusable. The affected documents are not just inconvenient—they're business-essential and their loss or corruption creates significant operational disruptions.

I would kindly ask you to fix this critical bug.

This is the file that is compromised in Word build version 2508:
compromised-file.pdf

A file with a .doc or .docx extension cannot be uploaded, so here is the .pdf version of the document.

Answer 2

Hi @Marin Grabovac,

Thank you for bringing this to our attention with such clarity. I fully understand the severity of the issue and the operational impact it’s having on your organization. The corruption of mission-critical reports due to changes in Word’s table rendering engine is deeply concerning, especially given the scale of affected users.

Based on your description and recent reports from the Microsoft community, it appears that Word version 2508 introduced changes to how tables are merged and rendered, particularly when paragraph breaks are programmatically removed between matrix-style tables. These changes can trigger horizontal overflow errors, resulting in unreadable or corrupted documents.

1/ Test on Earlier Word Builds

If possible, open the same reports in Word version 2507 or earlier. This can help confirm the regression and serve as a temporary workaround.

2/ Consider Adjusting Report Generation Logic

As a short-term mitigation, you might explore inserting minimal spacing or alternative formatting between tables to avoid triggering the merge algorithm.

3/ Submit a Support Ticket to Microsoft

I strongly recommend submitting this issue through your Microsoft 365 admin portal or via Microsoft Tech Community. The more detailed the report, the faster it can be prioritized. Engaging with Microsoft Support will allow you to work with agents who can provide live assistance and escalate the issue to specialized teams if needed. They also have the ability to perform deeper backend analysis and offer targeted solutions that go beyond what we can provide here in the forum.

We’re committed to supporting you through this and will do everything we can to help minimize disruption. I know this isn’t the outcome you were hoping for, and I sincerely wish I had a more effective solution to offer. Your feedback is incredibly valuable, and I encourage you to share it on the Microsoft Feedback Portal, where it can be reviewed out Product Department and supported by other users who may have the same issue. I encourage you to submit this feedback directly through Outlook by selecting Help > Feedback > Suggest a Feature or submitting your feedback through the Microsoft Feedback Hub. User's image

Sharing your experience through this channel is the most impactful way to advocate for a change that would benefit you and other users.

Thank you again for your patience and for bringing this to our attention. While I can't change the product's design, please don't hesitate to reach out if you have any other questions about its current functionality.

Please let me know if there's anything else I can assist you with and I’ll do my best to support you.

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Marin Grabovac 0 Reputation points

2025-09-13T12:21:56.26+00:00

Please report the bug, thank you.