Using PADS Layout and a 6-layer setup, I want to reduce the layer count to 4 by deleting two of the inner layers.
I deleted all "real" data on those inner layers. When I go to Layers Setup -> Electrical Layers -> Modify and choose 4 electrical layers, PADS Layout shows a report that there is still data on all of the six layers.
Having a look at the report, I see that all vias in the design are interpreted as data on all layers, although the vias have no pad on the layers I want to delete (the setting "remove unused pads" is active).
How can I delete two of the inner layers without deleting all the vias in the design?
P.S.: ASCII File export/import without exporting the PCB structure is not a good option since it messes up the layer definition