What is the difference between ScanDisk and CHKDSK?

ScanDisk and CHKDSK are disk utility tools in Microsoft Windows operating systems that allow users to scan, diagnose, and repair issues with storage drives. ScanDisk was first introduced in Windows 95 and was replaced by CHKDSK starting in Windows XP. Both tools serve the purpose of checking storage drives for errors and attempting to fix any problems detected. While they share some similarities, there are also key differences between ScanDisk and CHKDSK in terms of capabilities and usage. This guide provides an overview of each tool, compares their features and limitations, and offers guidance on when to use each one.

What is ScanDisk?

ScanDisk is a disk checking utility that was originally created by Symantec Corporation and included with MS-DOS and Windows 9x operating systems. It first appeared in MS-DOS 6.0 and Windows 3.1. ScanDisk analyzes hard disks for problems and can correct many issues such as bad sectors, lost clusters, and directory errors. ScanDisk was later included in the Windows 9x line of operating systems up through Windows ME.

ScanDisk scans your hard drive to look for various disk errors or corruption. Some key things that ScanDisk checks for include:

  • Lost file allocation table (FAT) and directory entries
  • Clusters marked “bad” in the FAT
  • Invalid FAT and directory entries
  • Cross-linked files
  • Directory tree errors

If ScanDisk detects any errors, it will prompt you and give you the option to fix the errors it finds. ScanDisk can recover readable data from corrupted directories and bad sectors by marking those areas as unusable and reassigning data to properly working areas of the disk.

What Does ScanDisk Do?

ScanDisk is a disk utility that scans storage devices for errors and tries to repair them. Some of its main functions include:

Detecting and fixing various file system errors – ScanDisk can detect and repair invalid file system structures, cross-linked files, directory errors, invalid security descriptors, bad clusters, and lost clusters, among other errors.CHKDSK vs ScanDisk vs SFC vs DISM Windows 10

Recovering data from bad sectors – If ScanDisk detects bad sectors on the disk, it attempts to repair them and recover data stored there. This helps retrieve important files and information.How to Scandisk Windows 10

Optimizing disk space usage – ScanDisk can consolidate fragmented files and folders to optimize space usage. This helps improve disk performance.

In summary, ScanDisk focuses on scanning disks for errors, fixing various file system problems, recovering data from bad sectors, and optimizing disk usage.

Limitations of ScanDisk

ScanDisk has some key limitations compared to CHKDSK that are important to understand:

ScanDisk is primarily designed for floppy disks and other removable media, so it lacks some of the more advanced features that CHKDSK offers for analyzing and repairing hard drives. ScanDisk cannot detect or fix issues like bad sectors, cross-linked files, or directory errors which CHKDSK is designed to handle.

Additionally, ScanDisk does not work directly with the NTFS file system like CHKDSK does. So ScanDisk may not be able to fully optimize or repair drives formatted with NTFS. Some experts warn that forcing ScanDisk to scan NTFS drives could possibly lead to further corruption.

ScanDisk also lacks options for some of CHKDSK’s more advanced repair capabilities. For example, ScanDisk cannot recover data from bad sectors the way CHKDSK can when run with the /R option. And ScanDisk does not have an equivalent to CHKDSK’s /F parameter to fix errors in the file system.

In summary, for basic maintenance of removable media, ScanDisk may suffice. But for more comprehensive analysis and repair of hard drives, especially those formatted with NTFS, CHKDSK is the more capable and recommended utility.

What is CHKDSK?

CHKDSK (pronounced “check disk”) is a system utility in Microsoft Windows that checks the integrity of the file system and fixes logical file system errors. It was first introduced in MS-DOS and has been included in every version of Windows since then.

CHKDSK was developed by Microsoft as part of the MS-DOS operating system in the 1980s. It was designed to scan the file system, check for issues like bad sectors, lost clusters, cross-linked files, and directory errors, and then repair any problems it finds.

The utility works by traversing the file system in a logical order, verifying the integrity of each metadata structure it encounters. If it finds errors, it tries to fix them automatically. Some errors require a scheduled reboot to fix.

Over the years, CHKDSK has been updated and enhanced. But its core purpose – to check and repair file system issues – has remained the same since its inception.

Today, CHKDSK continues to ship with all versions of the Windows operating system and remains an essential tool for diagnosing and repairing disk problems.

What Does CHKDSK Do?

CHKDSK is a command-line utility built into Windows that allows users to scan, diagnose, and repair issues with their hard disk drives. The main functions of CHKDSK are:

Scan the drive to check for various errors and issues such as bad sectors, lost clusters, cross-linked files, directory errors, invalid security descriptors, and more. CHKDSK will scan the volume bitmap and file system metadata to identify any inconsistencies or corruption [1].

Diagnose and report any issues found during the scan process. CHKDSK will provide details on the errors detected and their locations on the drive.

Repair any file system errors or corruption that is found. CHKDSK can fix bad sectors, recover readable information, recover lost clusters, fix cross linked files, etc. The /F parameter tells CHKDSK to attempt to repair any issues [2].

Recover readable information from bad sectors and attempt to relocate that information to properly functioning locations on the hard disk. This helps recover data from dying drives.

Overall, CHKDSK helps keep hard drives healthy, identifies issues, prevents further data loss or corruption, and recovers data where possible.

Comparing ScanDisk and CHKDSK

ScanDisk and CHKDSK are similar disk checking and repair utilities, but there are some key differences between the two:

ScanDisk was the disk checking tool included in Windows 95 through Windows Me. It allowed for basic hard drive checks and repairs. CHKDSK first appeared in Windows NT and later replaced ScanDisk completely starting in Windows 2000. CHKDSK is more robust and includes additional capabilities compared to ScanDisk.

Some of the key differences between ScanDisk and CHKDSK include:

  • CHKDSK works on NTFS, FAT, exFAT, ReFS, and other filesystems. ScanDisk only works on FAT and FAT32 drives.
  • CHKDSK detects and repairs a wider range of disk errors and problems compared to ScanDisk. For example, CHKDSK can fix filesystem corruption issues that ScanDisk cannot.
  • CHKDSK provides more information during its checks such as total disk space, free space, filenames, and more. ScanDisk provides more basic disk details.
  • CHKDSK includes additional switches and options not found in ScanDisk, such as being able to check disks on restart and fix filesystem problems automatically.
  • As a newer tool, CHKDSK has more updated capabilities to check larger, modern drives. ScanDisk is limited to older hardware.

Overall, CHKDSK superseded ScanDisk as a more powerful, versatile disk checking utility and has become the standard on modern Windows versions. ScanDisk lacks many of the useful features of CHKDSK.

Which is Better and When to Use Each

Both ScanDisk and CHKDSK have their strengths and weaknesses. Here are some guidelines on when each tool is more appropriate:

Use ScanDisk if:

  • You need a quick and basic check of your disk drives for errors.
  • You want an easy-to-use graphical interface.
  • You don’t need to fix errors, just detect them.

ScanDisk is faster but less thorough than CHKDSK. It’s good for a quick scan if you just want to check for and identify problems.

Use CHKDSK if:

  • You want a more comprehensive scan that will go sector by sector.
  • You need to actually repair disk problems, not just detect them.
  • You are comfortable with running from the command line.
  • You need more detailed reporting and logging of results.

CHKDSK takes longer but provides more detailed analysis and the ability to fix many errors automatically. It’s better for recovering from disk problems.

So in summary:

  • Use ScanDisk for a quick, basic surface scan and error check.
  • Use CHKDSK for an in-depth scan and to repair disk problems.

Running both together provides a comprehensive check and the ability to detect and repair disk errors.

Using ScanDisk and CHKDSK Together

ScanDisk and CHKDSK can complement each other when diagnosing and repairing disk issues. While CHKDSK focuses on repairing the file system structure, ScanDisk specializes in recovering lost files and folders. Using both together provides a comprehensive solution.

A good practice is to first run CHKDSK to fix any file system errors. This ensures the disk is in a stable state for ScanDisk to then safely recover files without causing further corruption. Once CHKDSK has repaired the structural issues, ScanDisk can salvage files that may have been lost or corrupted when the file system problems occurred.

Some experts recommend running CHKDSK using the /F and /R options first, followed by ScanDisk 1. The /F switch fixes errors on the disk while /R locates bad sectors and recovers readable data. This 1-2 combo allows for repairs to the disk itself, followed by restoration of damaged and deleted files.

In summary, using CHKDSK and ScanDisk together provides both preventative and restorative maintenance. CHKDSK proactively fixes issues to avoid potential file corruption or loss, while ScanDisk recovers files lost due to those issues. This robust disk and data care regimen can optimize disk health and longevity.


In summary, ScanDisk and CHKDSK are utilities for checking and repairing hard disk issues, but they work in different ways and have some key differences:

  • ScanDisk is a Microsoft tool focused on fixing logical file system errors. It checks file system integrity and scans for invalid or corrupt files.
  • CHKDSK is more robust and low-level. It checks the physical disk itself for bad sectors and errors. CHKDSK also fixes file system errors.
  • ScanDisk has limited repair capabilities while CHKDSK can fix a wider range of disk problems.
  • ScanDisk is easier to use and more user-friendly. CHKDSK works from the command line and has more advanced options.
  • ScanDisk works on FAT and NTFS drives. CHKDSK works on FAT, NTFS, and other file systems.

In general, for simple disk checking and repair, ScanDisk provides a quick and easy option. But for serious disk diagnostic and repair needs, CHKDSK is more powerful and effective. Using both together as part of regular disk maintenance can help optimize disk health and performance.