Your file system has marked the drive as dirty. This indicates that some problem has been detected. The dirty flag will not be removed until you complete a pass of chkdsk on the drive to repair the problem in the file system. OR you can turn off the check in the registry (generally bad idea), or you can run the file system utility and clear the flag (sometimes ok to do for various reasons)
fsinfo.exe can be used to clear or repair the file system (google for how to use)
- if the problem comes back after you do the repair, there can be other reasons for this
depending on what OS version you are running, what controller and the version of the driver you are running.