Put a note for the fabricator to not create this 0mm layer. In two layer stackup, set the thickness as 0 mm for the second layer. Preparing Fabrication Data in Altium Designer | Altium Designer 23 User Manual | Documentation Make sure your through hole pads remain as through hole pads, as you will need the drill information. Rather than providing them with the full set of Gerber files, you generally only need to plot the layers they want, to produce this PCB.

Then check with your fab house to see how they prefer to receive information on single layer PCBs. To create a single-sided/one layer PCB within current versions of Altium Designer, you need to make sure the copper is all on the desired side of the PCB (everything on the top layer.or everything on the bottom layer). To fix those issues, in AD21.3, the ability to remove the bottom layer had been disabled again. In early versions of AD21 it was possible to remove the bottom layer, but this was not a supported feature and caused some unwanted issues in other functions of Altium Designer. Solution Details The Altium Layer stack manager does not currently allow for removal of top or bottom layer due to a limitation with drill pairs where at least two layers are assumed to exist. How do I define a single layer (single sided) board in the layer stack manager? I have two layers, but Layer Stack Manager won't let me delete one of the signal layers.

Altium designer schematic