Invalid MS-DOS function is an error that may stop you from moving, deleting, copying, or renaming a file on your Windows computer. Do you know what does invalid MS-DOS function mean? Do you know how to effectively get rid of this issue? In this post, MiniTool Software will show you some available solutions.

What Does Invalid MS-DOS Function Mean?

Invalid MS-DOS Function is an error you may receive when you move, delete, copy, or rename a file on your computer. The error is shown as follows:

Invalid MS-DOS function

This is actually a file-system error that often influences the file functionality only. It is an annoying issue because it will stop you from operating the file normally. Besides, it can happen on all versions of Windows like Windows 10, Windows 8.1/8, and Windows 7.

Luckily, it is possible to get rid of this error. In the following parts, we collect some solutions that are proved to be effective. You can use one or a mix and match of these fixes to solve this invalid MS-DOS function Windows 10. If you are still using Windows 8.1/8/7, the steps are similar.

Solution 1: Optimize and Defragment the Drive

You can use the Windows snap-in tool to optimize and defragment the hard drive on your computer. You can follow these steps to do the job:

  1. Press Windows + E at the same time to open This PC. You can also just click This PC on the desktop to open it.
  2. Right-click on one drive and then go to Properties > Tools > Optimise > Optimise.

optimize and defragment the drive

Then, you can see the status of each drive. At last, you still need to reboot your computer to see whether the invalid MS-DOS function error disappears.

Solution 2: Run Hotfix

If you want to move a file from an NTFS format drive to a FAT32 format drive and encounter invalid MS-DOS function, you can run Hotfix to get rid of the issue.

Solution 3: Run Reimage

A system corrupt can also cause Windows 10 invalid MS-DOS function. So, you can also use Reimage Plus to scan the repositories and replace corrupt and missing files. This solution can work in most cases. Now, you can click here to get Reimage Plus and then use it to kill the invalid MS-DOS function error.

Solution 4: Edit System Policy in Registry Editor

Some users said that they solved this issue by editing system policy in Registry Editor. Before doing this, you’d better back up the registry key in case something goes wrong.

Here, we will show you how to do this job on your computer:

1. Press Windows + R to open Run.

2. Type regedit and press Enter to access Registry Editor.

3. Navigate to the following path:


4. Right-click on the blank space on the right pane and then go to New > DWORD (32-bit) Value.

Edit System Policy in Registry Editor

5. Rename the value name as CopyFileBufferedSynchronousIo and press Enter.

6. Double-click on the new value to open it.

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

At last, you still need to reboot your computer and then check whether the Invalid MS-DOS Function error disappears.

Solution 5: Run CHKDSK

Using CHKDSK is also one solution that is proved to be effective to fix the invalid MS-DOS function error.

[SOLVED] CHKDSK Is Not Available for RAW Drives? See Easy Fix
[SOLVED] CHKDSK Is Not Available for RAW Drives? See Easy Fix

When you are facing CHKDSK is not available for RAW drives error, do you know how to fix it? Now, read this post to solve this issue without data loss.

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You can follow this guide to do the job:

  1. Open Command Prompt as Administrator.
  2. Type chkdsk /x /f /r and press Enter.
  3. You will receive a message saying 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). You need to press the Y key on the keyboard and then reboot your computer to let CHKDSK to check and fix the errors on the computer hard drive.

These are the solutions that can fix Invalid MS-DOS Function on your Windows computer. We hope they can help you out.

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