Fix Invalid MS-DOS Function file error on Windows 10

If when you try to move, delete, copy or rename files / folders in Windows 10 and you receive Invalid MS-DOS function Error message, then this post might interest you. In this article, we will identify some known potential causes that could trigger the error, and then provide possible solutions that you can try to resolve this problem.

It is actually a file system error which often only affects the functionality of the files. You may also experience the error if you try to move a file from an NTFS format drive to a FAT32 format drive and a corrupted system file can also trigger the error.

Invalid MS-DOS function file error

If you are faced with this Invalid MS-DOS function problem, you can try our recommended solutions below in no particular order and see if it helps to fix the problem.

1. Run CHKDSK
2. Shorten the name of the file you are copying
3. Optimize and defragment your drive
4. Format the destination drive in NTFS format
5. Create and configure CopyFileBufferedSynchronousIo registration key.

Let’s take a look at the description of the process involved in relation to each of the solutions listed.

1]Run CHKDSK

Using CHKDSK is also a solution that has proven to be effective in correcting Invalid MS-DOS function problem.

To run CHKDSK, follow these steps:

Press Windows key + R.

In the Run dialog box, type cmd then press CTRL + SHIFT + ENTER to open the command prompt in administrator / elevated mode.

In the command prompt window, type the command below and press Enter.

chkdsk /x /f /r

You will receive the following message:

Chkdsk cannot run because the volume is in use by another process. Do you want to schedule verification of this volume the next time the system is restarted? (WE).

press the Yes on the keyboard, then restart your computer to let CHKDSK check and correct errors on the computer’s hard drive.

When CHKDSK is complete, check if the problem is resolved.

2]Shorten the name of the file you are copying

In this solution, simply shortening the file name could help resolve the error when trying to move, delete, copy or rename files / folders in Windows 10.

If this fix does not work, you can try the following solution.

3]Optimize and defragment your drive

You can use the Windows snap-in to optimize and defragment your computer’s hard drive. You can follow these steps to get the job done:

• Press Windows key + E at the same time to open File Explorer.
• Click on This PC.
• Right-click the drive, then select Properties > Tools > Optimize > Optimize.

Once the procedure is finished, restart your PC and check if the Invalid MS-DOS function the problem is solved. Otherwise, go to the next solution.

4]Format the destination drive in NTFS format

If the destination drive is not formatted as a new technology file system (NTFS), you may experience the Invalid MS-DOS function Mistake. In this case, you can convert the destination drive to NTFS and see if it helps.

Here’s how:

Converting a drive using these steps will preserve the files on the drive. We always recommend that you make sure that you have backups of all files on the drive.

Find the drive letter you want to convert. Open File Explorer and, in the left pane, locate the drive under This PC or Computer.

Press the Windows logo key + R to open the Run dialog box.

Type cmd and press Enter to open the command prompt window.

At the command line prompt, type the command below and press Enter. Replace the drive: placeholder with the actual letter of the reader.

convert drive: /fs:ntfs

When the formatting process is complete, try the file action again and see if the problem is resolved. Otherwise, go to the next solution.

5]Create and configure CopyFileBufferedSynchronousIo registration key

Some users said they could fix the problem Invalid MS-DOS function problem in modifying the system policy in Registry Editor. Here’s how:

Since this is a registry operation, it is recommended that you back up the registry or create a system restore point if there is a problem.

Once you have taken the necessary precautionary measures, you can do the following:

Press Windows key + R.

In the Run dialog box, type regedit and press Enter to open the Registry Editor.

Browse or navigate to the registry key path below:

HKEY_LOCAL_MACHINESOFTWAREPoliciesMicrosoftWindowsSystem

Right-click the empty space in the right pane, then select New> DWORD Value (32-bit).

Rename the value name to CopyFileBufferedSynchronousIo and press Enter.

Double-click on the new value to open it.

Type 1 in the Value data box and press Enter to save the change.

You can now exit the Registry Editor and restart your PC. At startup, check if the problem is resolved.

Should either of these solutions solve the problem for you?