Could you supply me with some python code to do this task? It works well for me on linux, how about windows? An issue with trying to find out if a file is being used by another process is the possibility of a race condition. Ideally, the code in the print statement can be changed, as per the requirements of your program. If you do want to detect modifications to larger files in this manner, consider making use of the update() function to feed your file in chunks to the MD5 function, this is more memory efficient. It can actually be done in an OS-independent way given a few assumptions, or as a combination of OS-dependent and OS-independent techniques. It can actually be done in an OS-independent way given a few assumptions, or as a combination of OS-dependent and OS-independent techniques. On Mar 7, 6:28 am, "Ros"