Invalid MS-DOS Function Error in Windows 10 [SOLVED]

Fix Invalid MS-DOS function error in Windows 10: If you are facing the Invalid MS-DOS function error while trying to move, copy, delete, or rename files or folders then you are at the right place as today we are going to discuss on how to resolve the issue. The error doesn’t even let copy files from one folder to another and even if you try to delete some old pictures, chances are you will face the same error message. The files doesn’t have a read-only attribute or hidden and security settings are same, so the issue is quite mysterious itself for a normal Windows users.

Invalid MS-DOS Function Error in Windows 10 [SOLVED]

create a restore point  just in case something goes wrong.

Method 1: Defragment and Optimize Drives

1.Open Control Panel then click on System and Security.

2.From System and Security click on Administrative Tools.

3.Click on Defragment and Optimize Drives in order to run it.

4.Select your drives one by one and click on Analyze followed by Optimize.

5.Let the process run as it’s going to take some time.

6.Reboot your PC to save changes and see if you’re able to Fix Invalid MS-DOS function error in Windows 10.

Method 2: Registry Fix

Backup your registry before continuing.

1.Press Windows Key + R then type regedit and hit Enter.

2.Navigate to the following registry key:


3.Right-click on System then select New > DWORD (32-bit) value.

4.Name this DWORD as CopyFileBufferedSynchronousIo and double click on it to change it’s value to 1.

5.Exit registry and reboot your PC to save changes. Again see if you’re able to Fix Invalid MS-DOS function error in Windows 10 or not, if not then continue with the next method.

Method 3: Run CHKDSK

1.Press Windows Key + X then select Command Prompt (Admin).

2.Type the following command in cmd and hit Enter:

chkdsk C: /f /r /x

Note: Make sure you use the drive letter where Windows is currently installed. Also in the above command C: is the drive on which we want to run check disk, /f stands for a flag which chkdsk the permission to fix any errors associated with the drive, /r let chkdsk search for bad sectors and perform recovery and /x instructs the check disk to dismount the drive before beginning the process.

Fix File System Errors with Check Disk Utility(CHKDSK) .

4.Reboot your PC to save changes.

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That’s it, you have successfully Fix Invalid MS-DOS function error in Windows 10 but if you still have any queries regarding this guide then feel free to ask them in the comment’s section.