Because CHKDSK repairs a FAT file system usually through changing the disk's file allocation table, which can cause data loss. So, CHKDSK will display a confirmation message like this. During CHKDSK running, an error message similar to '10 lost allocation units found in 3 chains. It will remind you 'chkdsk cannot run because the volume is in use by 0x800420cd another process', 'Would you like