Make sure that you do not replace Windows Disk Defragmenter!
See this picture.
Why ? i disabled the windows defrag, if using defraggler then you dont need the windows one, especially since defraggler is identical in it scanning and file placement as windows defrag but just does it faster and more efficiently with a bundle of extra features like the boot time defrag, file defrag and many more customisations that are'nt available in windows defrag.