CHKDSK or Check Disk is a utility tool used by Windows operating system to scan and repair disk errors. When you run CHKDSK on a drive, it creates a log file for every scan it performs. These log files store information about the errors found on the disk, the status of the repair process, and other useful details.
The location of the CHKDSK log files depends on the version of Windows you are using. In Windows 10 and 8, the log files are stored in the "C:\\Windows\\Logs\\Windows" directory. In Windows 7 and earlier versions, the log files can be found in the "C:\\Windows\\Chkdsk.log" or "C:\\Windows\\Chkdsk.txt" directory.
Keep in mind that CHKDSK log files tend to become very large, so it's a good idea to save them to an external hard drive or cloud storage if you don't need them for immediate troubleshooting purposes.