jorb wrote:I'm wagering a guess that that is a forest tile and that those can't be paved directly. Dig it out to make it dirt, put the soil back to make it flat, try again.
There is not enough clearance to dig here. Also all the other tiles were forest ones. I plowed the area before placing stones, and this time I used the automatic (new) system to place all the stones. He just stoned all but this one.
Edit: Also i leveled most of the terrain before. "most" xD

The left area was done by my gf, the right one by me.