KB: Cannot define Single-Layer PCB
Created: April 08, 2025 | Updated: July 17, 2025
Altium Designer
If you cannot delete the top or bottom layer in a 2-layer PCB to define a single-layer PCB in the Layer Stack Manager, please make sure that the PCB.SingleLayerStack.Support and PCB.RigidFlex.SubstackPlanning options are enabled in the Advanced Settings dialog.
Solution Details
In version 24.8, the ability to define a Single-Layer PCB was added to Altium Designer.
This feature is available when the PCB.SingleLayerStack.Support option is enabled in the Advanced Settings dialog, which has been the default since version 25.0.
This requires that the PCB.RigidFlex.SubstackPlanning option is also enabled in the settings.
In the Layer Stack Manager, if you cannot delete the top or bottom layer in a 2-layer stack, you get a layer error for an existing single-layer PCB, or the single-layer stack is missing in the Tool » Presets menu, please make sure that both options are enabled. 
Delete is greyed out
Layer Error