How to solve PCB components removed and added after Import Changes or Update PCB Since v6.3.39, the schematic components and PCB components correspond with component ID, for solve the component removed and added after Import Changes in completely in new project. for the OLD PROJECT, the editor will re-assign the component ID base on the prefix. for example, schematic has R1, PCB has to have the R1. If your old schematic and PCB don't correct corresponding, then it will appear components removed and added. If your schematic and PCB component have the same prefixs, but still appear this issue, please try follow method to reset component ID: Method 1: 1, Make sure your editor version is v6.4.7 and geater. Check editor version: via Help - About  2, Open the schematic and PCB 3, Reset the component ID via: Top menu - Design - Reset Component ID，Schematic and PCB need to reset it both!  Notice: 1, If your schematic has subparts U1.1, U1.2 etc. after Import Change the U1 will be removed and added, because PCB doesn't have prefix U1.1 or U1.2 but U1. Please change PCB U1 to U1.1 or U1.2 etc, and then reset the compoment ID. the new project will not appear this issue. 2, Please don't edit the new design file at the lower editor version(less than v6.3.39).