i LOOKED INTO YOUR CODE , SUB THREADS ARE CREATED BUT DONT TRAVERSE BECAUSE THE GET WRONG PARAMETER : hThreads[numOfThreads]=CreateThread( /*create a new thread*/ NULL, 0, (LPTHREAD_START_ROUTINE) traverse, wfdData.cFileName ,/*send file name to new thread*/ 0, & threadID); wfdData.cFileName INCLUDES ONLY FILENAME WITHOUT THE FULL QUALIFIED PATH, YOu should send full path , anyway this program is very bad using so much threads (as a matter of fact using so many threads causes a deterioration with program behaviour : changing stack pointers mapping memory files , etc. Windows explorer uses -for example 1 additional thread for each window (IShellView) that is opened. GoodLuck. (use also const pointers LPCSTR=>LPCTSTR