NTFS (New Technology File System) stores virtually all kinds of files and folders on the hard drive with the help of special system files, called metadata files. One important metadata file is $Bitmap, which is also known as ‘Cluster Allocation Bitmap’. This metadata structure is located at 6th record of MFT and contains a map depicting used and unused cluster information.
In other words, $Bitmap represents information of volume clusters, which have been used and which are available for use. Practically, there can be instances that might corrupt this $Bitmap and necessitate you to perform some hard drive recovery operations and fix the problem.
MFT Bitmap corruption is a common problem and can occur for several reasons. You can detect these problems by running chkdsk command Apparently, it can also be detected when you try to copy some files to a drive, which is infected with $Bitmap corruption. On trying to copy the files, this might prompt you with errors like: