The Chkdsk Action runs the chkdsk.exe command line tool to check the integrity of your filesystem and optionally fix errors.
Specify the drive letter (followed by a colon), mount point, or volume name.
The disk must be locked. If chkdsk cannot lock the drive, a message appears that asks you if you want to check the drive the next time you restart the computer.
Displays the name of each file in every directory as the disk is checked and displays cleanup messages
The Fix errors option is implied. The disk must be locked.
All open handles to the drive are invalidated. The Fix errors option is implied.
Specify which error conditions reported by chkdsk should fail the action
Use with file allocation table (FAT) and FAT32 only. Specifies the location and name of a file or set of files that you want chkdsk to check for fragmentation. You can use wildcard characters (that is, * and ?) to specify multiple files.
Performs a less vigorous check of index entries, reducing the amount of time needed to run chkdsk.
Skips the checking of cycles within the folder structure, reducing the amount of time needed to run chkdsk.
Changes the log file size to the size you type.
More detailed information on chkdsk can be found on Microsoft TechNet here: