Blazor WebAssembly Template project does not work in case of publishing in VS Studio 2026 or 2022 Preview #64167
Description
This issue has been moved from a ticket on Developer Community.
[severity:I'm unable to use this version] [regression] [worked-in:Version 17.14.18 (October 2025)]
If I publish the template project without any modifications in the VS Studio 2022 Preview and 2026, the server start without any error, i can open the app in Chrome but the counter page immediately throws an error. The console says "instantiate_wasm_module() failed Link error:".
Without AOT compilation the counter still works, in case of AOT the counter does not work at all.
I have tried this on .net 9.0 and .net 10.0
Full console log:
blazor.web.js:1 [2025-10-25T11:54:33.212Z] Information: Normalizing '_blazor' to 'http://localhost:5000/_blazor'.
dotnet.runtime.drv0pr9n5o.js:3 MONO_WASM: instantiate_wasm_module() failed LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
Pe @ dotnet.runtime.drv0pr9n5o.js:3
dotnet.hqho1o2iry.js:3 MONO_WASM: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
at dotnet.runtime.drv0pr9n5o.js:3:179555
y @ dotnet.hqho1o2iry.js:3
dotnet.hqho1o2iry.js:3 Uncaught (in promise) LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
dotnet.hqho1o2iry.js:3 Uncaught (in promise) LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
dotnet.hqho1o2iry.js:3 Uncaught (in promise) LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
dotnet.hqho1o2iry.js:3 Uncaught (in promise) LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
dotnet.hqho1o2iry.js:3 Uncaught (in promise) LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
dotnet.runtime.drv0pr9n5o.js:3 Uncaught (in promise) LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
blazor.web.js:1 Uncaught (in promise) LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
blazor.web.js:1 Error in mono_download_assets: LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
gr @ blazor.web.js:1
counter:1 Uncaught (in promise) LinkError: WebAssembly.instantiate(): Import #31 "env" "mono_wasm_debugger_log": function import requires a callable
blazor.web.js:1 [2025-10-25T11:54:33.230Z] Information: WebSocket connected to ws://localhost:5000/_blazor?id=0wFjn1bOY-btqnFulCXVaQ.
Server command line:
info: Microsoft.Hosting.Lifetime[14]
Now listening on: http://localhost:5000
info: Microsoft.Hosting.Lifetime[0]
Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
Hosting environment: Production
info: Microsoft.Hosting.Lifetime[0]
Content root path: C:\Users\feren\source\repos\BlazorApp4\BlazorApp4\BlazorApp4\bin\Release\net9.0\publish
VS Studio 2026 Versions:
Visual C++ 2026 00487-20000-00000-AA130
Microsoft Visual C++ 2026
.NET MAUI Tools 18.0.328 (6b33afd9a4)
Visual Studio extension to enable .NET MAUI development.
.NET MAUI UI Tools 18.0.1.33 (remotes/origin/HEAD@44462085bc)
Visual Studio extension to enable .NET MAUI UI tools.
ADL Tools Service Provider 1.0
This package contains services used by Data Lake tools
ASA Service Provider 1.0
ASP.NET and Web Tools 18.0.328.14658
ASP.NET and Web Tools
Azure App Service Tools v3.0.0 18.0.328.14658
Azure App Service Tools v3.0.0
Azure Data Lake Tools for Visual Studio 2.6.5000.0
Microsoft Azure Data Lake Tools for Visual Studio
Azure Functions and Web Jobs Tools 18.0.328.14658
Azure Functions and Web Jobs Tools
Azure Stream Analytics Tools for Visual Studio 2.6.5000.0
Microsoft Azure Stream Analytics Tools for Visual Studio
C# Tools 5.0.0-2.25513.8+7463b65f5c25bd1e4180609bf8aaaa9436833a15
C# components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.
Cookiecutter 17.0.25266.3
Provides tools for finding, instantiating and customizing templates in cookiecutter format.
GitHub Copilot 18.0.911.22890
GitHub Copilot is an AI pair programmer that helps you write code faster and with less work.
Microsoft Azure Hive Query Language Service 2.6.5000.0
Language service for Hive query
Microsoft Azure Stream Analytics Language Service 2.6.5000.0
Language service for Azure Stream Analytics
Mono Debugging for Visual Studio 18.0.15 (76f6142551)
Support for debugging Mono processes with Visual Studio
NuGet Package Manager 7.0.0
NuGet Package Manager in Visual Studio. For more information about NuGet, visit https://docs.nuget.org/
Python - Profiling support 17.0.25266.3
Profiling support for Python projects.
Python with Pylance 17.0.25266.3
Provides IntelliSense, projects, templates, debugging, interactive windows, and other support for Python developers.
Rainbow Braces 1.0.170
Colorizes matching brace pairs to make it easy to identify them and their scope. Works for curly brackets, parentheses, and square brackets.
Razor (ASP.NET Core) 18.0.2.2551302+48a2659b91e7032c97ea024751a6ea9469a94d7f
Provides languages services for ASP.NET Core Razor.
SQL Server Data Tools 18.0.146.1
Microsoft SQL Server Data Tools
Test Adapter for Boost.Test 1.0
Enables Visual Studio's testing tools with unit tests written for Boost.Test. The use terms and Third Party Notices are available in the extension installation directory.
Test Adapter for Google Test 1.0
Enables Visual Studio's testing tools with unit tests written for Google Test. The use terms and Third Party Notices are available in the extension installation directory.
ToolWindowHostedEditor 1.0
Hosting json editor into a tool window
TypeScript Tools 18.0.0912.2001
TypeScript Tools for Microsoft Visual Studio
Visual Basic Tools 5.0.0-2.25513.8+7463b65f5c25bd1e4180609bf8aaaa9436833a15
Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.
Visual F# Tools 18.0.0-rc2.25455.2+1614065b2e732a13982b3cd7b629ca83593d1c67
Microsoft Visual F# Tools
Visual Studio IntelliCode 2.2.3152.23957
AI-assisted development for Visual Studio.
VSColorOutput64 2023.4
Color output for build and debug windows - https://mike-ward.net/vscoloroutput
VSPackage Extension 1.0
VSPackage Visual Studio Extension Detailed Info
The working 2022 versions:
Microsoft Visual Studio Community 2022
Version 17.14.18 (October 2025)
VisualStudio.17.Release/17.14.18+36616.10.-october.2025-
Microsoft .NET Framework
Version 4.8.09221
Installed Version: Community
Visual C++ 2022 00482-90000-00000-AA124
Microsoft Visual C++ 2022
ASP.NET and Web Tools 17.14.128.55757
ASP.NET and Web Tools
Azure App Service Tools v3.0.0 17.14.128.55757
Azure App Service Tools v3.0.0
Azure Functions and Web Jobs Tools 17.14.128.55757
Azure Functions and Web Jobs Tools
C# Tools 4.14.0-3.25412.6+c167adef821b9ba2f1c44c227a5e79ca11876461
C# components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.
Common Azure Tools 1.10
Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.
Cookiecutter 17.0.25079.8
Provides tools for finding, instantiating and customizing templates in cookiecutter format.
GitHub Copilot 17.14.1347.20289
GitHub Copilot is an AI pair programmer that helps you write code faster and with less work.
Microsoft JVM Debugger 1.0
Provides support for connecting the Visual Studio debugger to JDWP compatible Java Virtual Machines
Mono Debugging for Visual Studio 17.14.11 (f3bc644800)
Support for debugging Mono processes with Visual Studio
NuGet Package Manager 6.14.1
NuGet Package Manager in Visual Studio. For more information about NuGet, visit https://docs.nuget.org/
Python - Profiling support 17.0.25079.8
Profiling support for Python projects.
Python with Pylance 17.0.25079.8
Provides IntelliSense, projects, templates, debugging, interactive windows, and other support for Python developers.
Razor (ASP.NET Core) 17.14.3.2530601+3372435431977e91904a23ceb1eab689badc1bd9
Provides languages services for ASP.NET Core Razor.
SQL Server Data Tools 17.14.26.0
Microsoft SQL Server Data Tools
Test Adapter for Boost.Test 1.0
Enables Visual Studio's testing tools with unit tests written for Boost.Test. The use terms and Third Party Notices are available in the extension installation directory.
Test Adapter for Google Test 1.0
Enables Visual Studio's testing tools with unit tests written for Google Test. The use terms and Third Party Notices are available in the extension installation directory.
TypeScript Tools 17.0.40502.2001
TypeScript Tools for Microsoft Visual Studio
Visual Basic Tools 4.14.0-3.25412.6+c167adef821b9ba2f1c44c227a5e79ca11876461
Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.
Visual F# Tools 17.14.0-beta.25230.7+c1a9d78ad4a474a716ccffb4367ed5151e3f7c9f
Microsoft Visual F# Tools
Visual Studio IntelliCode 2.2
AI-assisted development for Visual Studio.
VisualStudio.DeviceLog 1.0
Information about my package
VisualStudio.Mac 1.0
Mac Extension for Visual Studio
VSPackage Extension 1.0
VSPackage Visual Studio Extension Detailed Info
Xamarin 17.14.271 (bf42fb0072)
Visual Studio extension to enable development for Xamarin.iOS and Xamarin.Android.
Xamarin Designer 17.14.3.0 (tags/main-61034a2(11307611)^0@61034a2622)
Visual Studio extension to enable Xamarin Designer tools in Visual Studio.
Xamarin.Android SDK 13.2.2.0 (d17-5/45b0e14)
Xamarin.Android Reference Assemblies and MSBuild support.
Mono: d9a6e87
Java.Interop: xamarin/java.interop/d17-5@149d70fe
SQLite: xamarin/sqlite@68c69d8
Xamarin.Android Tools: xamarin/xamarin-android-tools/d17-5@ca1552d
Original Comments
Feedback Bot on 10/27/2025, 05:54 AM:
We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.