I have continued the warrior’s head by doing the ear and connecting the rest of the face parts. I had to fix the topology redirection edge loops to avoid pools of six edges or many pools one next to the other. During this process I worked only with half of the head. When I finished it I duplicated it and inverse scaling it by -1in the correct axis. My computer had worst problems of memory and crashes than when I did the blue’s retopology. I have lost a lot of time today due to this. At the end of the day I discovered that one way to solve this problem. This is to delete the history very frequently to not overcharge the undo option and to eliminate a lot of accumulated transforming information.