DiskTuna (formerly DiskTune) is a tiny and free disk defragmentation and optimization software that will run only when you want it to. DiskTuna does not install background services or other crapware that slows the system down.
DiskTuna is safe: It relies on the proven and reliable Windows defrag API to do the actual file moves. It checks the volume state prior to defragmentation. DiskTuna features a VSS safe-mode to reduce interaction between defragmentation and shadow copies and a thermal monitor to protect your hard disk from overheating.
DiskTuna is capable of moving and defragmenting the MFT online.