'The parameter is incorrect' when opening a drive or copying files
How do I fix 'the parameter is incorrect' error?
Written by The CommonFixes team · fact checked by CommonFixes review desk
Last updated
Short answer
It nearly always means the file system table on that drive is damaged, usually from unplugging it while it was still writing. The data is normally still there; Windows just cannot read the index that says where everything lives. Occasionally it is a decimal symbol setting or a file whose date is invalid. The quickest thing to try first: stop writing to the drive — Do not format it and do not save anything else to it. Every extra write reduces what can be recovered. Most people are done in about 20 minutes.
Full walkthrough below: 6 steps for Windows, rated careful.
Sounds like this
- •Double clicking a drive shows the message instead of opening it
- •A copy stops part way with the same wording
- •An external disk or SD card suddenly behaves this way
Why it happens
It nearly always means the file system table on that drive is damaged, usually from unplugging it while it was still writing. The data is normally still there; Windows just cannot read the index that says where everything lives. Occasionally it is a decimal symbol setting or a file whose date is invalid.
Work through these in order
0% done- 1
Stop writing to the drive
Do not format it and do not save anything else to it. Every extra write reduces what can be recovered.
- 2
Run chkdsk on it
Note the drive letter, open Command Prompt as administrator and run: chkdsk X: /f /r (replace X). Let it finish, which can take an hour on a large disk. This rebuilds the index and fixes most cases outright.
- 3
Check the decimal symbol
If the error appears while copying files rather than opening a drive, go to Control Panel, Region, Additional settings, and make sure Decimal symbol is a full stop and not a comma. It sounds odd but it is a real, documented cause of this exact message during copies.
- 4
Retry the copy with a tool that can resume
In Command Prompt run: robocopy "D:\source" "E:\destination" /E /R:1 /W:1. Robocopy skips the one bad file and reports it instead of aborting the whole job like Explorer does.
- 5
Update or reseat the connection
Try a different USB port and cable, preferably a rear port on a desktop. A flaky lead causes half finished writes, which is what damaged the index in the first place.
- 6
Recover the data, then format
If chkdsk cannot fix it, run a free tool such as Recuva or TestDisk to pull the files off to another disk. Once your data is safe, right click the drive and format it fully, not quick, to rebuild the file system from scratch.
If none of that worked
If chkdsk reports bad sectors or the drive clicks, it is failing physically. Copy off whatever still opens right now and replace the drive; further scans can finish it off.
Did this fix work for you?
A quick thumbs up helps other readers find the guides that actually work.
Share this fix
Related fixes worth reading
Chosen automatically from the 157 guides on CommonFixes, based on how closely they match this problem.
Windows update fails with 0x80070057
How do I fix Windows update error 0x80070057?
USB drive shows 0 bytes and will not format
How do I fix a USB flash drive that shows 0 bytes, RAW format and cannot be formatted?
A file says no app is associated with it
What does 'this file does not have an app associated with it' mean?
Drag and drop stops working in Windows 11
How do I fix drag and drop not working on the Windows 11 desktop or in folders?
A drive asks to be formatted
My flash drive says you need to format the disk before you can use it. Are my files lost?
USB stick does not show up
I plugged in my USB drive and nothing happens. How do I get my files?
Still not it? Browse every fix or see more in files and storage.
Who wrote this and how we checked it
The CommonFixes team
Writer and researcher
We are a small group of people who spend our days repairing laptops and desktops for family, friends and small offices. Every guide here starts with a problem someone actually brought to us, and we only write down the steps that put the machine right.
- Everyday repairs
- Windows and Mac
- Plain language
CommonFixes review desk
Technical editor
Before a guide goes live, a second person walks through it on a real machine and checks each instruction against the maker's own support pages. Anything we cannot confirm is removed rather than guessed at.
- Fact checking
- Safety warnings
- Source links
This guide was last updated on 10 August 2026. If a step no longer matches what you see on screen, tell us on the contact page and we will test it again.
A gentle reminder: back up anything you cannot afford to lose before major repairs. If a step ever feels risky, stop and ask a technician. There is no shame in that.