Anyone have a good tutorial/guide for using winhex to edit the NTFS files such as $MFTMirr ? The problem I had seems to have come from compacting the MFT or something I think. On drives where bootdefrag would no longer work, I moved my files, reformatted within Windows and boottime defrag worked again even with 16KB clusters .... so it's not an incompatibility with 16KB clusters My 16KB cluster size system disk has an only 4KB $MFTMirror and I cannot edit it .... I've tried to edit and it's always locked or access denied - booting in windows in BartPE, in DDOS, etc. etc. I've used a boot disk to use TestDisk and when it asks me if I want to rewrite the $MFTMirr using the MFT and I answer Yes the system auto reboots and nothing was changed Nothing I can do allows me to edit or access or overwrite the $MFTMirr Suggestions Please ! I don't want to reformat yet if I don't have to and besides, doing this will be a good learning experience for any future issues Thanks !