This post explains why the Windows 7 USB/DVD Download Tool (WUDT) is unable to copy the install files to the USB drive in some cases. The tool allows you to create a copy of your Windows 7 ISO file on a USB flash drive.
Latest posts by Michael Pietroforte (see all)

Update: If you have problems Windows 7 USB/DVD Download Tool you can try the free alternative Rufus. The most powerful tool for creating a bootable Windows setup flash drive is WinSetupFromUSB.

You might have heard of the stir that Microsoft's Windows 7 USB/DVD Download Tool (WUDT) caused last year when some Open Source watchmen recognized that the tool contained code that violated the GPL. Microsoft was then "forced" to release WUDT under GPLv2. Considering the upset in the media about this incident, I expected a luxurious tool that comes with lots of customization features. I was somewhat disappointed to discover it does nothing else but copy the contents of a Windows 7 install DVD to a USB stick and make it bootable.

Windows-7-USB-DVD-Download Tool-WUDT

The funny thing is that WUDT even failed to perform this simple task with my no-name USB stick. This message was the only thing that the Open Source tool could do for me:

We were unable to copy your files. Please check your USB device and the selected ISO file and try again.

At least, my cheap stick wasn't the cause because everything worked perfectly when I manually did the job (hopefully without violating any Open Source laws). So, I thought, I would write this post for those who might run into the same problems and think they need to buy another USB stick. After all, this is Microsoft software and there are not many options to integrate bugs in such a simple tool.

Anyway, here is what you have to do. Launch a command prompt with admin rights and run the diskpart tool. Note: Before you run these commands read the warning below!

list disk
select disk #
create partition primary
select partition 1
format quick fs=fat32

The "list disk" command will show you the connected drives and with "select disk", you can choose your USB stick.

WARNING: Be careful to select the right drive or else your day won't have a happy end because if you select the wrong drive you will lose all your data on this drive!

The crucial step here is the "clean" command. It overwrites the MBR and the partition table (thereby, deleting everything on the stick). My guess is that WUDT misses this step and only formats the flash drive. It appears my memory stick had some odd partitions (which is not uncommon). When I tried WUDT again with this prepared stick, the Open Source tool mastered its task without further murmur.

By the way, this is also the reason why you shouldn't use the Windows Disk Management applet to prepare the USB stick. This GUI doesn't offer a clean command.

After you prepare the stick, you have to copy the contents of your Windows 7 DVD to the thumb drive, and you are done. If you only have an ISO file, you can use Virtual CloneDrive to mount the Windows 7 install DVD first.

Instead of formatting the partition with FAT32, you can also use NTFS (like WUDT does), but then you need an extra step to make the drive bootable:

Bootsect.exe /nt60 X:

"X:" is the drive letter of your USB stick. Bootsect.exe can be found on the Windows 7 DVD in the boot folder. However, I can't really recommend using NTFS. My USB stick, at least, appeared to be slower with NTFS.

  1. Ranveer Singh 11 years ago

    This seriously helped me a lot..!! thankyou you brother..!

  2. MK 11 years ago

    Your instructions worked on a Sandisk Cruzer 16 GB whereas the MS tool did not!

  3. Cacus 11 years ago

    Worked perfectyl! I Thank you very much!

  4. Reg E Barclay 11 years ago

    Thank you, my good man, the advice you provided was accurate and successfully resolved my issue. It seems that the Microsoft provided tool is unable to cope with drives >32GB, as it will not format them with the FAT32 partition table. Manually creating the boot disk using NTFS was the solution. Your guide provided me with the missing link; the bootsec.exe step was one that I had missed.

  5. Thomas Iversen 11 years ago

    Thanks alot dude! That did the trick!

  6. Gus 11 years ago

    Unfortunately, the disk part did not work either. The format quick fs=fast32 resulted in a incompatible file system error.

    Simpler solution for me: Use Windows Explorer to format USB Stick with FAT32 (which works interestingly), then start Windows Download Tool again. Now works fine.

  7. Dustin 11 years ago

    Thank you, sir! The Windows USB Tool was giving me fits but this simple fix got the ball rolling.

  8. Gopal Bhat 11 years ago

    Thank you very much.
    I was having the same problem and your method sorted it out 🙂

  9. Antonio 11 years ago

    Thank you very much. Now the program is working perfectly and it’s able to copy my windows 8 iso into the pen drive!

  10. NICHOLE 11 years ago


  11. Koray 11 years ago

    Thanks a lot for this valuable information, you saved my day!



  12. Atif 11 years ago

    I have done all above method on 2 usb with 2 Iso files. but both of them were unsuccessful for me . i have win8 iso file . i dont know what is problem , i have changed the USBs , any help please

  13. Amin 11 years ago

    Thank you very much! It was helpful for me.

  14. David Bock 11 years ago

    Thanks for that great solution.

  15. René 11 years ago

    Thanks for the commands. The reason why this error message appears at my installation was that avira antivirus tool blocked the autorun.inf of the windows iso-file I tryed to copy to the USB stick. Unchecking this function in the antivirus tool made WUDT doing its job. 😉

  16. Seán 11 years ago

    Thanks a bunch. Worked perfectly.

  17. Kuroneko 11 years ago

    Works perfectly.

  18. zib 11 years ago

    did the job. nice work. thank you very much!

  19. Dani menur 11 years ago

    Thank you very much… Worked perfectly

  20. Daniel 11 years ago

    Just deactivate the “block autorun” function of you firewall and /or anti virus software. i´m using avira antivir as antivirus program and had the same problem. after deactivation of the block autorun function it just went well.. cheers

  21. sohan 11 years ago

    Flawless victory! Thanks a lot dude

  22. Nopez 11 years ago

    My drive was formatted with the NTFS file system, and this guide steps you through formatting it as FAT32. I guess the Microsoft USB tool is only FAT32 compatible.

  23. luis 11 years ago

    Thanks! worked great for me too.

  24. benson 11 years ago

    Thank you. Though I’m a bit confused about the magic commands(diskpart, xxx, xxx)

    Anyway, this method indeed works.

  25. Matt 11 years ago

    Thank you very much good sir!

Leave a reply to Matt Click here to cancel the reply

Please enclose code in pre tags

Your email address will not be published. Required fields are marked *


© 4sysops 2006 - 2023


Please ask IT administration questions in the forums. Any other messages are welcome.


Log in with your credentials


Forgot your details?

Create Account