Hyper-V Manager Quick Create Fails with "Cannot load file or assembly Newtonsoft.Json"

Question

Creating a new virtual machine using Hyper-V Manager in Windows 11 24H2 results in the following error message:

Attempts to resolve the issue include removing and reinstalling Hyper-V and the .NET Frameworks, as well as running SFC /Scannow and DISM /Online /Cleanup-Image /RestoreHealth, but the problem persists.

Additionally, Visual Studio 2022 Community is installed, and Newtonsoft.Json is present in at least one project, with the latest version being 13.0.3.

Answer 1

Hey Stephen,

Possible Causes:

1. Version Mismatch in Newtonsoft.Json

The application (Hyper-V Manager or another system component) expects Newtonsoft.Json version 12.0.0.0, but a different version (like 13.0.3) is installed.

If a newer version is installed globally or referenced by another application, it may cause a conflict.

2. Corrupted Assembly or Incorrect Installation

The installed Newtonsoft.Json package might be corrupt.

The manifest file in the GAC (Global Assembly Cache) or application directory might not match the expected version.

3. System File Corruption

Even though you ran SFC and DISM, some underlying system dependencies might still be causing an issue.

4. Conflicting .NET Versions

If multiple .NET versions are installed, the Hyper-V Manager might be picking up an incorrect dependency.

------------------Solutions that you can try------------------

1. Check the Installed Newtonsoft.Json Versions

Open PowerShell and run:

Get-Package -Name Newtonsoft.Json

If multiple versions are installed, you may need to uninstall conflicting versions.

2. Force Install Newtonsoft.Json 12.0.0.0

Open PowerShell as Administrator and run:

Install-Package Newtonsoft.Json -Version 12.0.0

Alternatively, if using NuGet in Visual Studio:

Open NuGet Package Manager.

Search for Newtonsoft.Json.

Downgrade to version 12.0.0.

3. Manually Add Binding Redirects

Navigate to:

C:\Windows\Microsoft.NET\Framework\v4.0.30319\Config\machine.config

or (for 64-bit)

C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Config\machine.config

Add the following inside the <configuration> section:

<configuration>

<runtime>

<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">

  <dependentAssembly>

    <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral" />

    <bindingRedirect oldVersion="0.0.0.0-13.0.3.0" newVersion="12.0.0.0" />

  </dependentAssembly>

</assemblyBinding>

</runtime>

</configuration>

Restart the computer and try again.

4. Clear the Global Assembly Cache (GAC)

Open Command Prompt (Admin) and run:

gacutil /l Newtonsoft.Json

If multiple versions exist, remove the incorrect ones:

gacutil /u Newtonsoft.Json

Reinstall version 12.0.0.0.

5. Repair .NET Framework

Open Command Prompt (Admin) and run:

dotnet --list-runtimes

If any installations seem broken, reinstall .NET Framework:

Go to Settings → Apps → Installed Apps.

Find .NET Framework, click Modify, and choose Repair.

6. Reinstall Hyper-V (Again)

If the issue persists, try:

Uninstall Hyper-V completely using PowerShell:

Disable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All

Restart your PC.

Reinstall Hyper-V:

Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V-All -All