LykosAI/StabilityMatrix · error · ValidationException

Model not selected

Error message

Model not selected

What it means

Thrown in SvdImgToVidConditioningViewModel.ApplyStep when the VideoLinearCFGGuidance node is created but e.Builder.Connections.Base.Model is null — i.e. no upstream model card has produced a model output yet. SVD conditioning must chain from a loaded checkpoint, so a missing base model connection fails validation.

Solutions

1. Ensure the SVD/img2vid model card step runs before the conditioning step so Base.Model is populated
2. Select and load a checkpoint in the model card (fix any earlier 'Model not selected' failure)
3. Reorder or re-enable the model card module in the workflow before the conditioning module

Example fix

// before
conditioningVm.ApplyStep(args); // Base.Model null -> throws
// after
if (args.Builder.Connections.Base.Model is null) { modelCardVm.ApplyStep(args); }
conditioningVm.ApplyStep(args);

if (args.Builder.Connections.Base.Model is null)
    throw new ValidationException("Run the model card step before SVD conditioning");

bool hasBaseModel = args.Builder.Connections.Base.Model is not null;

try { conditioningVm.ApplyStep(args); }
catch (ValidationException ex) when (ex.Message == "Model not selected") { /* run/repair the model card step first */ }

When it happens

Trigger: ApplyStep executed with e.Builder.Connections.Base.Model == null when adding the ComfyNodeBuilder.VideoLinearCFGGuidance node (Model = ... ?? throw).

Common situations: The SVD model card step was skipped, disabled, or its ApplyStep failed, leaving Base.Model unset; cards ordered incorrectly in the workflow so the loader never ran; preset missing the model card entirely.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Model not selected
• Length cannot be null when latentType is Hunyuan
• Invalid Token
• Model file name must contain a valid file name.
• Prompt extensions not installed

AI-assisted analysis of LykosAI/StabilityMatrix@af93d6ef57 (2026-09-12). Data as JSON: /api/errors/bd67fa1df2bfea22. Report an issue: GitHub.

Appendix: source

Thrown at StabilityMatrix.Avalonia/ViewModels/Inference/Video/SvdImgToVidConditioningViewModel.cs:75

        return parameters with
        {
            FrameCount = NumFrames,
            MotionBucketId = MotionBucketId,
            Fps = Fps,
            AugmentationLevel = AugmentationLevel,
            MinCfg = MinCfg,
        };
    }

    public void ApplyStep(ModuleApplyStepEventArgs e)
    {
        // do VideoLinearCFGGuidance stuff first
        var cfgGuidanceNode = e.Nodes.AddTypedNode(
            new ComfyNodeBuilder.VideoLinearCFGGuidance
            {
                Name = e.Nodes.GetUniqueName("LinearCfgGuidance"),
                Model =
                    e.Builder.Connections.Base.Model ?? throw new ValidationException("Model not selected"),
                MinCfg = MinCfg
            }
        );

        e.Builder.Connections.Base.Model = cfgGuidanceNode.Output;

        // then do the SVD stuff
        var svdImgToVidConditioningNode = e.Nodes.AddTypedNode(
            new ComfyNodeBuilder.SVD_img2vid_Conditioning
            {
                ClipVision = e.Builder.Connections.BaseClipVision!,
                InitImage = e.Builder.GetPrimaryAsImage(),
                Vae = e.Builder.Connections.Base.VAE!,
                Name = e.Nodes.GetUniqueName("SvdImgToVidConditioning"),
                Width = Width,
                Height = Height,
                VideoFrames = NumFrames,
                MotionBucketId = MotionBucketId,

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