Autorouter since days didn't finish my route. But it is simple to do so. So I fixed 2 missing tracks manually. The Problem here is the ATMEGA328P series of VCC - GND - VCC - GND following pins no 3 to 6.  I filled it manually as follows:  I tried hours with small rearrangements if parts to hope that the router did it self. I think such pattern should be detected and handled properly. I also fixed the processors manual tracks and hoped that autorouter does the rest, but no, he rearranges around in an awful manner. Means, if you have added something manually then you must finish manually. There seems no detection to accept some existing tracks in reusing them. In general I found out that the 4th layer isn't really efficiently used. But when I pay for 4 layers, all layers should be used without prioritizing the layers 1 and 2. These are requirements, not bugs. best regards Frank