Why is my Simulink Desktop Real-Time simulation slow or halts in Windows when Hyper-V is enabled?

I am trying to use Simulink Desktop Real-Time (SLDRT) on my Windows machine, but when I run the example model "sldrtex_vdp.slx", it runs slowly, halts, or may even cause a bluescreen. The following warning or error messages may be shown:

Warning: The "Real-Time Synchronization" block has timed out while trying to synchronize to real-time kernel.
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Model sldrtex_vdp loaded
A disconnect message was sent to the target 10 seconds ago. Waiting for response.. [6 similar]
Never received disconnect response from target. Disconnecting...
Model sldrtex_vdp unloaded
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Warning: The Hyper-V hypervisor has been detected. The Simulink Desktop Real-Time kernel cannot run in the presence of the hypervisor. Please disable the Hyper-V operating system component before attempting to use Simulink Desktop Real-Time.
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Warning: The Hyper-V hypervisor has been detected. The Simulink Desktop Real-Time kernel is unable to run in the presence of the hypervisor. Please disable the Hyper-V operating system component before attempting to use Simulink Desktop Real-Time.

Answer 1

[MathWorks Support Team]

Depending on the MATLAB release used, Simulink Desktop Real-Time (SLDRT) has different levels of compatibility with Microsoft Hyper-V:

• In MATLAB R2022b and earlier, the SLDRT kernel is not compatible with Hyper-V or any features that rely on Microsoft virtualization technology (e.g., WSL/WSL2). If Hyper-V is enabled, SLDRT cannot load and start the real-time kernel, and you will see error messages indicating this failure. Disabling Hyper-V is mandatory when using MATLAB R2022b or prior versions. To run a virtual machine, you could, for example, use VMWARE.
• In MATLAB R2023a and later, the SLDRT kernel includes support for Hyper-V. However, this does not guarantee full compatibility on all systems. In some cases, SLDRT may still fail to run correctly when Hyper-V is enabled. If you encounter issues such as halts, crashes, kernel load failures, or limited performance, you should disable Hyper-V as a troubleshooting step, even on newer releases. In some cases, enabling Hyper-V may even be necessary to use SLDRT R2023a and later, as explained in this MATLAB Answer.

Steps to disable Hyper-V:

Disable Hyper-V on your Windows 10 or Windows 11 PC by performing the following steps:

1. Find Turn Windows features on or off by using Windows search.

2. Clear the boxes for the following features, as shown in the screenshot below:

• Hyper-V
• Virtual Machine Platform
• Windows Hypervisor Platform
• Windows Subsystem for Linux

This operation begins the uninstall process.

3. Restart the computer as prompted after the uninstall process completes.

Further Troubleshooting:

If the above steps don't help, please see the following MATLAB Answers post for troubleshooting steps:

How do I troubleshoot issues with disabling the Windows Hyper-V feature for SLDRT?