FastReport.OpenSource.Web 2026.2.x WebReport preview blank page on .NET 10

[jrsistemasltda]

Describe the bug
After upgrading FastReport.OpenSource.Web from version 2025.2.0 to versions 2026.2.0 and 2026.2.1, the WebReport preview stopped working in an ASP.NET Core MVC application running on .NET 10.

The report loads and Report.Prepare() executes successfully, but the preview page becomes blank.
The browser console shows errors related to:

• webreport-script.bundle.min.js
• styles.min.css

Additionally, the _content/FastReport.OpenSource.Web assets are not correctly exposed in runtime.

Downgrading all FastReport packages back to 2025.2.0 fixes the issue immediately without any code changes.

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To Reproduce
Steps to reproduce the behavior:

1. Create or open an ASP.NET Core MVC project using .NET 10

2. Install:

   • FastReport.OpenSource 2026.2.0 or 2026.2.1
   • FastReport.OpenSource.Web 2026.2.0 or 2026.2.1

3. Configure:

   builder.Services.AddFastReport();
   app.UseFastReport();

4. Create a controller returning:

   return View(webReport);

5. Create a view with:

   @model FastReport.Web.WebReport
   
   @await Model.Render()

6. Open the report preview

7. The page becomes blank and the WebReport scripts fail to load correctly

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Expected behavior
The WebReport preview should render normally, exactly as it works in version 2025.2.0.

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Stacktrace
No server exception occurs.

Observed behavior:

• Blank preview page
• webreport-script.bundle.min.js loads empty
• _content/FastReport.OpenSource.Web assets are missing or invalid
• Browser console reports script/css loading errors
• Report.Prepare() works correctly

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Screenshots
Browser console shows errors related to:

• webreport-script.bundle.min.js
• styles.min.css

The preview page renders completely blank.

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Device (please complete the following information):

• OS: Windows 11
• Browser: Chrome
• Version: Latest

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Additional context
Environment:

• ASP.NET Core MVC
• .NET 10
• Visual Studio 2026

Tested versions:

• 2026.2.0 → failed
• 2026.2.1 → failed
• 2025.2.0 → works correctly

Additional notes:

• Report.Prepare() executes successfully
• Controller and View remained unchanged
• Problem appears related to Static Web Assets / _content resources in FastReport.OpenSource.Web

[BogdanStg]

Hello!

I was able to reproduce the issue, created a ticket, and forwarded it to our developers. We will notify you as soon as a solution is available.