CHKDSK (short for check disk) is a system tool built in to the Windows operating system that scans your hard drive for file system errors and will generally fix them.
Running the CHKDSK utility will also check and repair hard drive errors by finding “dead sectors” on the drive and attempting to retrieve the data inside those sectors.
Issues with the file system and dead sectors can often be the cause of computers running slowly or feeling “buggy” when in use.
Run CHKDSK From File Explorer
The easiest and quickest way to run a chkdsk is from within File Explorer. This will only check the file system of the hard drive, but can often give you a clue as to whether you need to take your computer offline and run a more extensive disk check.
Open File Explorer and then click on This PC in the left hand navigation pane.
Right click on your system drive (usually the C: drive).
On the options menu, left click Properties.
Check Drive
When the Properties window opens, click the Tools tab.
Then in the Error Checking section click on the Check button.
You’ll probably see a message pop up “You don’t need to scan this drive”.
That doesn’t mean that the drive is OK. It simply means that Windows hasn’t detected anything yet.
To scan anyway, click on Scan Drive.
When the CHKDSK scan has finished you can either click the Close button if no errors were found.
Or click the Show Details link if it reports problems.
Run CHKDSK From Command Prompt.
CHKDSK works best when run from the command prompt. This is because it’ll take your drive offline and will scan both the file system and the surface of the drive for errors.
If you still suspect you might have issues after running the Error Checking, then this is the next step.
Open a command prompt by clicking the Start button and then typing “cmd“. Right click on Command Prompt and then left click Run As Administrator.
CHKDSK Command
Using the command prompt isn’t like using Windows. There’s no point and click option. You have to type commands in manually. But it is very powerful.
At the command prompt, type chkdsk followed by a space, then letter of the drive that you want to scan, another space and then what’s called the switch.
The switch is how you can tell CHKDSK what sort of scan it should do. By far the most common switches to use on a home computer is /r switch.
The completed command will look like this –
chkdsk c: /r
When that’s done, hit Enter on your keyboard.
Repairing Hard Drive On Home Computer Using CHKDSK
There are many switches that you could use with the CHKDSK utility. But by far the most useful when trying to repair a hard drive on your home PC is the /r switch.
The /r switch forces chkdsk to scan and repair the file system if errors are found. And then to scan the surface of the drive looking for dead sectors.
For a full list of all the CHKDSK switches and what they do click https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/chkdsk?tabs=event-viewer
Cannot Lock Current Drive
If you’re running chkdsk on your system drive you’ll see this message appear in the Command Prompt window.
“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? (Y/N)“
What it means is that chkdsk requires exclusive access to the drive. It can’t operate properly if while Windows is running.
To continue, type the letter “Y” and then press the Enter key.
To begin the scan, restart your computer.
The computer will reboot and the scan will start.
Using CHKDSK with the /r switch, there will be 5 stages.
The first 3 are file system scans, and the final 2 are disk scans.
How Long Should It Take?
A chkdsk /r scan can take many hours to complete. It all depends on your computer and the hard drive that’s being scanned.
SSD’s will be obviously be scanned much quicker. Maybe 30 minutes or less. For mechanical drives (spinning drives), they can take several hours depending on the size and condition of the drive.
Backup Before Running CHKDSK
CHKDSK scans the hard drive looking for bad sectors. If it finds any, it’ll try to recover and data that’s stored within those sectors.
After that the dead sectors will be marked as unusable so that Windows doesn’t try to save any data into that area of the drive.
There is always a slight chance that in doing so, you could lose important data (files). It doesn’t happen often, but it does happen.
Before initiating a chkdsk /r scan, always backup any important files on your computer. Even if it’s just copying and pasting a few files onto a memory stick How To Copy Files Or Folders To A USB Flash Drive.
Summary.
You can use CHKDSK to help identify and fix issues with the hard drive and file system when your computer isn’t running well. Particularly if it seems to be slowing down.
Then follow up by running a system file check How To Run System File Checker (SFC).
But you can also use it to help prevent those same issues from becoming a problem by using it on a schedule. Depending on use, run CHKDSK every 3 to 6 months.
