The race condition is when another program is interacting with that directory too. So you check that the directory exists, and then the other program gets CPU time and uses it to delete that directory, and then your program tries to delete that directory but fails.
To avoid this, you have to either get a lock on that directory somehow (opening a transaction), or you have to try deleting the directory and then check the return code or catch any exceptions to tell whether the directory existed at the time of the attempted deletion.
To avoid this, you have to either get a lock on that directory somehow (opening a transaction), or you have to try deleting the directory and then check the return code or catch any exceptions to tell whether the directory existed at the time of the attempted deletion.