Troubleshooting

Before baking: validation

Clicking any bake button first validates every node involved. If validation fails, nothing is baked and the problems are listed in the log (see Interface for where that log appears). Common messages:

Message	Meaning
Settings missing	The node’s Settings socket (Mesh/Pass/Output) is unconnected and no Recipe Settings node in the tree is pinned. Either connect an Override node directly, or pin a Recipe Settings node.
Input error: No valid inputs connected	The node has no upstream connection that resolves to usable data — e.g. a Bake Pass with nothing plugged into its Mesh socket.
Target error: No valid target objects selected	A mesh-input node’s Target socket is empty, or resolves to zero valid objects. Target is the one socket that must always be filled.
UV error: No UV Maps found on object	A target mesh has no UV map at all — add one before baking.
UV error: Selected UV map not present on object	A specifically picked UV map was deleted or renamed since being selected on that object entry.
Multires error: No multires data on object	Selected a Multiresolution pass on an object without a Multiresolution modifier (or with zero subdivision levels).
Material warning: not a node based material	A material on a target/source doesn’t use nodes at all — PBR passes need a node-based material with a Principled BSDF. This is a warning, not a hard failure, unless it’s the only material and check_materials blocks the bake outright.
Material warning: Output doesn’t appear to be a valid combination of Principled and Mix shaders	The material has nodes, but Bake Wrangler couldn’t trace a valid Principled BSDF chain into the material output — PBR pass results may be incorrect.
Output error: No valid outputs connected	You clicked bake on a node with nothing valid connected downstream of it (only relevant when baking from an “upstream” node like a Bake Pass rather than an Output node directly).
Path error: Invalid path	The output folder doesn’t exist and either Create Paths is off in preferences, or it couldn’t be created.
File error	A problem opening, reading, or writing the destination image file — for example, a file already exists at that path but isn’t actually a readable image.
Pre/Post-Script file error / compile error	A Batch Bake pre- or post-bake script (external file or internal text block) couldn’t be opened, or failed to compile due to a syntax error.

Recipes from an older add-on version

Each recipe (node tree) records the add-on version that last touched it. Open the Recipe Info panel in the Bake Node Editor’s side panel to compare:

• Recipe version < Add-on version — the recipe was made with an older Bake Wrangler and can be upgraded automatically. Click Update Recipe in the panel. This rewires and updates nodes in place to match the current format; back up your file first if the recipe is complex, since node structure can change significantly between major internal versions.

• Recipe version > Add-on version — you’re opening a recipe made with a newer version of the add-on than you currently have installed. Update the add-on itself; an automatic downgrade isn’t offered.

• Very old recipes (from format versions before automatic upgrade support was added) show Update Unavailable — these will need to be rebuilt manually in a current version.

The background bake process

Because baking runs in a separate, background Blender instance (see Interface), a few classes of problem are specific to that setup:

• A bake seems to hang or never finish — check the log overlay (or the BakeWrangler text block) for what the background process is currently doing; very high sample counts, large resolutions, or CPU-only OSL passes (Height, Curvature-OSL, Bent Normals) can take a long time. You can always click Cancel Bake to stop it.

• A bake fails immediately with no useful log output — try disabling Disable Add-ons in preferences temporarily; a third-party add-on active in the background instance may be crashing it. Enabling Debug Output also adds more detail to the log.

• Results look like they’re using stale data — remember the background process bakes from a saved copy of your file. Save before baking if you’ve made changes you expect to be reflected.

• A bake fails partway through a long batch and you don’t want to start over — enable Retry in preferences; Bake Wrangler will automatically retry from the last point it made measurable progress, rather than restarting from scratch, as long as further progress continues to be made.

Vertex color output not appearing on my mesh

Vertex color bakes are staged, not applied automatically. After the bake completes, click Apply on the Output Vertex Colors or Batch Bake node that produced them — see Interface and Output Nodes.

Getting help

If you’re stuck, the Blender Artists forum thread is the best place to ask — include the relevant portion of your bake log (with Debug Output enabled in preferences, if possible) and a description of your node setup.