Hi Manu, What does the Design Manager show under the Nets and DRC Errors sections? ![enter image description here][1] Try saving the file, closing it and then reopening it. This can sometimes clear leftover ratlines. [1]: /editor/20160930/57ed5228adfe3.png

Well ... I've many errors on Nets and DRC errors ... To solve problem, i've imported change with import button ![][1] [1]: /editor/20160930/57ee279545f0d.png Redo autorouter process and all blue line desappeered ... Thanks for your help (i've never seen this interresting menu ;-)) Manu

@Emmanuel.Malosse if you don't use the import button, what happen if you change the schematic? We always need to martch the schematic to PCB.

Hi Manu, Although it is possible to create a schematic and a PCB design separately or even a PCB with no schematic in EasyEDA, the fastest and most reliable way is to start with a schematic, add all the part numbers, packages, supplier part numbers and a brief part description to each part (remember that if all the information is added to one part, it can be copied and pasted to all other instances of the same part). * Include any mounting holes in the PCB in the schematic (see later). Check the schematic using the Schematic Design Manager. That gets the schematic and the BoM information right so parts can then be ordered. Next, pass the schematic through to PCB using the **Convert to PCB...** button at the top of the Schematic Editor window. Do the layout. Check the PCB using the PCB Design Manager. Any required circuit changes should be made to the **Schematic** and those passed into the PCB using the **Import Changes...** button at the top of the PCB Editor window. This brings the PCB up to date with the schematic. * This is why holes should be included in the schematic. If they are not then they will be deleted from the PCB every time the **Import Changes...** button is pressed! Edit the layout to accommodate the changes. Check the PCB using the PCB Design Manager. Then see: https://easyeda.com/forum/topic/Essential_checks_before_placing_a_PCB_order-UuohztL3l :)

Thanks for this complete answer ... All is clear ;-) Thanks also for your beautiful job for this tools. Very, very useful !!!! Manu