LykosAI/StabilityMatrix · error · ValidationException

Model not selected

Error message

Model not selected

What it means

Thrown in ImgToVidModelCardViewModel.ApplyStep when building an image-to-video workflow with an ImageOnlyCheckpointLoader but no checkpoint model selected. The loader requires a CkptName, so SelectedModel == null aborts graph construction with this ValidationException.

Solutions

1. Select an image-only checkpoint (e.g. svd.safetensors) in the model dropdown
2. Download the required checkpoint via Model Manager if none is installed
3. Re-point the preset/selection to an existing model file

Example fix

// before
await vm.ApplyStep(args); // SelectedModel null -> throws
// after
if (vm.SelectedModel is null) { throw new ValidationException("Select an img2vid checkpoint first"); }
await vm.ApplyStep(args);

if (vm.SelectedModel is null)
    throw new ValidationException("Select an image-only checkpoint before img2vid generation");

bool hasCheckpoint = vm.SelectedModel is not null;

try { vm.ApplyStep(args); }
catch (ValidationException ex) when (ex.Message == "Model not selected") { /* prompt checkpoint selection */ }

When it happens

Trigger: ApplyStep executed with SelectedModel == null when the ImageOnlyCheckpointLoader node is created (CkptName = SelectedModel?.RelativePath ?? throw).

Common situations: User opened the Image-to-Video (SVD/ImageOnly) card without downloading or picking an image-only checkpoint; the previously selected checkpoint was deleted or renamed; preset references a missing model.

Understand the failure class

Background: "is required", "must be set", "missing required field": configuration validation errors across open-source libraries — this error's family across 36 libraries.

Related errors

• Model not selected
• No VAE Selected
• No Clip1 Selected
• No Clip2 Selected
• Model not selected

AI-assisted analysis of LykosAI/StabilityMatrix@af93d6ef57 (2026-09-12). Data as JSON: /api/errors/3868b286a67bb94b. Report an issue: GitHub.

Appendix: source

Thrown at StabilityMatrix.Avalonia/ViewModels/Inference/Video/ImgToVidModelCardViewModel.cs:46

            clientManager,
            vmFactory,
            tabContext,
            settingsManager,
            modelIndexService,
            notificationService,
            modelOrganizationService
        )
    {
        DisableSettings = true;
    }

    public override void ApplyStep(ModuleApplyStepEventArgs e)
    {
        var imgToVidLoader = e.Nodes.AddTypedNode(
            new ComfyNodeBuilder.ImageOnlyCheckpointLoader
            {
                Name = "ImageOnlyCheckpointLoader",
                CkptName = SelectedModel?.RelativePath ?? throw new ValidationException("Model not selected"),
            }
        );

        e.Builder.Connections.Base.Model = imgToVidLoader.Output1;
        e.Builder.Connections.BaseClipVision = imgToVidLoader.Output2;
        e.Builder.Connections.Base.VAE = imgToVidLoader.Output3;
    }
}

View on GitHub (pinned to af93d6ef57)