How to locate fuslogvw.exe on my machine?

Fuslogvw.exe

locate fuslogvw

.NET debugging

Windows tools

software troubleshooting

How to locate fuslogvw.exe on my machine?

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Introduction

fuslogvw.exe (Assembly Binding Log Viewer, also called Fusion Log Viewer) is a .NET Framework diagnostic tool that logs and displays assembly binding failures. When your .NET application throws FileNotFoundException or FileLoadException for an assembly, Fusion Log Viewer shows you exactly which paths the runtime searched, what version was requested, and why binding failed. The tool ships with the Windows SDK and Visual Studio, but its exact location varies by installed SDK version.

Common File Locations

The tool is installed as part of the Windows SDK or Visual Studio. Search these paths depending on your installation:

1# Visual Studio 2022
2C:\Program Files\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.8.1 Tools\fuslogvw.exe
3C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.8 Tools\fuslogvw.exe
4
5# Visual Studio 2019
6C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.8 Tools\fuslogvw.exe
7C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.7.2 Tools\fuslogvw.exe
8
9# Visual Studio 2017
10C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.6.1 Tools\fuslogvw.exe
11
12# Older .NET Framework SDKs
13C:\Program Files (x86)\Microsoft SDKs\Windows\v8.1A\bin\NETFX 4.5.1 Tools\fuslogvw.exe
14C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\bin\fuslogvw.exe

Finding It Quickly

Using Windows Search

powershell

1# PowerShell — search all drives
2Get-ChildItem -Path "C:\Program Files*" -Recurse -Filter "fuslogvw.exe" -ErrorAction SilentlyContinue
3
4# Faster: search only the SDK directory
5Get-ChildItem -Path "C:\Program Files (x86)\Microsoft SDKs" -Recurse -Filter "fuslogvw.exe"

Using Command Prompt

cmd

where /R "C:\Program Files (x86)" fuslogvw.exe
where /R "C:\Program Files" fuslogvw.exe

Using the Developer Command Prompt

Visual Studio's Developer Command Prompt adds SDK tools to the PATH:

cmd

# Open "Developer Command Prompt for VS 2022" from the Start menu
fuslogvw
# The tool launches directly — no path needed

The Developer Command Prompt is the easiest way to access fuslogvw.exe without knowing its exact path.

Installing if Missing

If fuslogvw.exe is not found, install the Windows SDK or the .NET Framework development tools:

1# Option 1: Visual Studio Installer
2# Open Visual Studio Installer → Modify → Individual Components
3# Check ".NET Framework 4.8 targeting pack" or similar
4
5# Option 2: Windows SDK
6# Download from https://developer.microsoft.com/windows/downloads/windows-sdk/
7
8# Option 3: .NET Framework Developer Pack
9# Download the targeting pack for your .NET Framework version

Using Fusion Log Viewer

Enabling Logging

Fusion logging is disabled by default. Enable it in the tool or via the registry:

11. Run fuslogvw.exe as Administrator
22. Click "Settings"
33. Select "Log bind failures to disk" (or "Log all binds to disk" for verbose)
44. Set a custom log path (optional)
55. Click OK

Via registry (alternative):

reg

1# Enable fusion logging
2reg add "HKLM\SOFTWARE\Microsoft\Fusion" /v ForceLog /t REG_DWORD /d 1 /f
3reg add "HKLM\SOFTWARE\Microsoft\Fusion" /v LogPath /t REG_SZ /d "C:\FusionLogs\" /f
4reg add "HKLM\SOFTWARE\Microsoft\Fusion" /v LogFailures /t REG_DWORD /d 1 /f
5
6# Disable when done (important for performance)
7reg delete "HKLM\SOFTWARE\Microsoft\Fusion" /v ForceLog /f
8reg delete "HKLM\SOFTWARE\Microsoft\Fusion" /v LogPath /f

Reading the Log

After enabling logging and reproducing the assembly binding failure:

11. Click "Refresh" in fuslogvw.exe
22. Find the failed binding entry
33. Double-click to see the full log:
4   - Which assembly was requested (name, version, culture, public key token)
5   - Which paths the runtime probed
6   - Why binding failed (version mismatch, file not found, etc.)

A typical log entry shows:

1Assembly manager loaded from: C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll
2Running under executable: C:\MyApp\MyApp.exe
3LOG: Attempting download of new URL file:///C:/MyApp/MyLibrary.dll
4LOG: Attempting download of new URL file:///C:/MyApp/MyLibrary/MyLibrary.dll
5ERR: Failed to complete setup of assembly (hr = 0x80070002). Probing terminated.

.NET Core / .NET 5+ Alternative

fuslogvw.exe only works with .NET Framework. For .NET Core and .NET 5+, use different diagnostic tools:

bash

1# Enable assembly binding diagnostics via environment variable
2set COREHOST_TRACE=1
3set COREHOST_TRACEFILE=trace.log
4dotnet run
5
6# Or use dotnet-trace
7dotnet tool install --global dotnet-trace
8dotnet-trace collect --process-id <pid>

You can also add diagnostic logging in code:

csharp

1// In Program.cs for .NET 6+
2using System.Runtime.Loader;
3
4AssemblyLoadContext.Default.Resolving += (context, name) =>
5{
6    Console.WriteLine($"Failed to resolve: {name.FullName}");
7    return null;
8};

Common Pitfalls

Not running as Administrator: fuslogvw.exe requires Administrator privileges to enable logging and read registry settings. Running without elevation shows an empty log viewer with no entries.
Forgetting to disable logging after debugging: Fusion logging writes a log file for every assembly binding in every .NET application on the machine. Leaving it enabled degrades performance significantly and fills disk space. Always disable logging when done.
Looking in the wrong SDK directory: Multiple SDK versions can coexist. The fuslogvw.exe version must match the .NET Framework version your app targets. If you have both x86 and x64 versions, use the one matching your application's architecture.
Using fuslogvw.exe for .NET Core/.NET 5+ apps: Fusion Log Viewer only works with .NET Framework (up to 4.8). For .NET Core and .NET 5+, use COREHOST_TRACE environment variables or dotnet-trace instead.
Not refreshing after reproducing the failure: Fusion Log Viewer does not auto-refresh. After reproducing the assembly binding failure in your application, click "Refresh" in the viewer to load new log entries.

Summary

fuslogvw.exe is located in C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.x Tools\
Use the Developer Command Prompt for Visual Studio to launch it without knowing the path
Search with Get-ChildItem (PowerShell) or where /R (cmd) if the exact path is unknown
Run as Administrator and enable "Log bind failures to disk" in Settings
Always disable fusion logging when finished — it impacts all .NET applications on the machine
For .NET Core / .NET 5+, use COREHOST_TRACE=1 instead of fuslogvw.exe