Thank you for reply. I do have your pthread link on my new machine. I will try working with this newer approach to ld and its libraries. I definitely will study "this thread" link to bring me up-to-date. Appreciate your help. Dave

Thank you for the reply. I verified that the pthread library in not on my computer by: Apple linker ld uses the -L/usr/lib directory that issues the pthread not found error message. "ls /usr/lib" command does not show it. Using find across the complete disk did not find it. "find / | grep libpthread". I attached file yyy.txt giving various outs proving this. The find wild search output across the complete disk is not included due to its size. yyy.txt Dave