Troubleshooting
How to Run CHKDSK in Windows 11 and Read the Results
Written by Windows 11 Field Guide Editorial Team · Updated
When a drive starts acting oddly (files that will not open, folders that look empty, a message asking you to scan and fix a drive, or a PC that runs a disk check by itself at startup), the built-in check disk tool is the first thing to try. This guide shows how to run CHKDSK in Windows 11 from File Explorer and from the command line, what the main switches do, why it often wants to run at restart, and how to read the results afterwards.
The steps apply to Windows 11 version 24H2, 25H2 and 26H2, on both SSDs and hard drives.
What CHKDSK does (and does not do)
Microsoft describes chkdsk as a tool that checks the file system and file system metadata of a volume for logical and physical errors. In plain terms, it checks the drive’s index of files and folders: which file lives where, which space is free, and whether those records agree with each other.
Three points are easy to miss:
- Run without switches, it only reports. It does not fix anything until you add /f, /r, /x or /b.
- It is not a hardware test. It can find and mark bad sectors, but it does not tell you how worn an SSD is. For that, see check SSD health in Windows 11.
- It does not repair Windows itself. Damaged system files are a job for SFC /scannow and DISM /RestoreHealth.
Before you run it
If the drive holds files you care about and it is already showing errors, copy them somewhere else first. A repair changes the file system, and on a failing drive the extra reading can be the last straw. If you hear clicking or grinding from a hard drive, skip the repair and back up immediately.
On a laptop, plug in the charger. A check that runs at startup can take a long time and should not be cut short by a flat battery.
Method 1: Error checking in File Explorer
This is the simplest way and works for internal and external drives.
- Open File Explorer and select This PC.
- Right-click the drive and select Properties.
- Open the Tools tab and select Check under Error checking.
- If Windows says you do not need to scan the drive, you can still select Scan drive to check it.
- If errors are found, Windows offers to repair them. For the drive Windows runs from, it may ask to restart and repair during startup.
Method 2: Run CHKDSK from the command line
The command line gives you more control. Microsoft notes that you need to be an administrator, so right-click Start and select Terminal (Admin), then run one of these commands (replace C: with the drive letter you want to check).
| Command | What it does | When to use it |
|---|---|---|
| chkdsk C: | Reports the state of the volume; fixes nothing | A quick look |
| chkdsk C: /scan | Runs an online scan on an NTFS volume | Routine check while you keep working |
| chkdsk C: /f | Fixes errors; needs the drive locked | When errors were found |
| chkdsk C: /r | Everything /f does, plus finds bad sectors and recovers readable data | Suspected bad sectors |
| chkdsk C: /spotfix | Runs spot fixing on an NTFS volume | Quick targeted repair after /scan finds issues |
| chkdsk E: /f /x | Forces an external or data volume to dismount first, then fixes it | A data drive that is in use |
Microsoft also documents /i and /c for NTFS, which skip some checks to save time; leave them out unless you know you need a faster, lighter pass.
Why CHKDSK wants to run at restart
To fix errors, chkdsk must lock the drive so nothing else writes to it. Windows cannot lock the drive it is running from, so when you run chkdsk C: /f you see a message along the lines of “Chkdsk cannot run because the volume is in use by another process. Would you like to schedule this volume to be checked the next time the system restarts?”
Type Y and restart. The check runs before Windows loads, fixes what it can, and for the boot partition Microsoft notes it restarts the PC automatically when it finishes. Do not switch the PC off during this stage. Microsoft advises against interrupting chkdsk, although it adds that an interrupted run should not leave the volume more corrupt than before and that running it again should repair any remaining corruption.
For a data drive or USB stick, close any files open on it and chkdsk can usually lock it straight away, so no restart is needed.
How long it takes on SSDs and hard drives
The time depends on the switch and the drive. An online /scan is usually quick. Microsoft notes that /f on a large disk or one with millions of files can take a long time, and that /r on a large hard drive reads every sector, so runs of several hours are not unusual.
SSDs are much faster because there is no moving head. Microsoft’s guidance is that running chkdsk on an SSD is not dangerous, but repeated full-surface scans with /r add unnecessary write and erase cycles, so keep /r for real suspicion of bad sectors rather than routine use.
Read the CHKDSK results
If chkdsk ran in a terminal, the report is on screen. If it ran at startup, the text flashes past, but Windows saves it:
- Press Windows key + R, type eventvwr.msc and press Enter.
- Expand Windows Logs and right-click Application, then select Filter Current Log.
- In Event sources, tick Chkdsk and Wininit, then select OK.
- Open the most recent entry to read the full report.
Chkdsk also returns an exit code that scripts can read: 0 means no errors were found, 1 means errors were found and fixed, 2 means cleanup was performed or skipped because /f was not used, and 3 means the disk could not be checked or errors were not fixed.
What to do next
- Errors fixed, problem gone: keep an eye on the drive and make sure your backups run. Windows 11 File History is an easy start.
- Errors keep coming back: the drive may be failing. Check its health, copy your files off and plan a replacement.
- Windows still misbehaves: run SFC and DISM next, then work through the Windows 11 troubleshooting guide.
- Files went missing after a repair: on FAT and FAT32 drives chkdsk can save lost chains as File0000.chk-style files in the root folder; otherwise try the steps in recover deleted files in Windows 11.
If you want to reorganise a drive after checking it, see partition a hard drive in Windows 11 or, for removable drives, format a USB drive in Windows 11.
Frequently asked questions
Is it safe to run CHKDSK in Windows 11?
Yes. Microsoft says interrupting it is not recommended, but even an interrupted run should not leave the volume more corrupt than before. Back up important files first if the drive is already showing errors.
What is the difference between chkdsk /f and /r?
/f fixes file system errors. /r does everything /f does and also locates bad sectors and recovers readable information from them, which makes it much slower.
Why does CHKDSK ask to run at the next restart?
To fix errors, CHKDSK must lock the drive. Windows cannot lock the drive it is running from, so it offers to check C: during the next startup instead.
Should I run CHKDSK on an SSD?
Occasional checks are fine. Microsoft notes that repeated full-surface scans with /r add unnecessary writes, so use /scan or /f for routine checks and keep /r for real suspicion of bad sectors.
How long does CHKDSK take?
An online /scan is usually quick. /f on a large drive with many files can take a long time, and /r on a large hard drive can run for hours because it reads every sector.
Is CHKDSK the same as SFC?
No. CHKDSK checks the file system on a drive. SFC checks and repairs Windows system files. They solve different problems and are often run one after the other.
Sources
Windows 11 Field Guide Editorial Team
Editorial team
The Windows 11 Field Guide team writes and updates independent Windows 11 guides and checks each step against Microsoft's documentation and the current Settings app.
