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. Paschalis 11 years ago

    1. My AVG antivirus is turned off.
    2. Format with FAT32.
    3. Run BOOTSECT X: /nt60 /mbr /force
    4. Tried Acronis Disk Director to format & modify partitions.

    Above steps have been tried and still DISKPART didn’t show my USB stick. Therefore, I can’t proceed with CLEAN command.

    What seems to be the problem?

    Please help. Thank you.

  2. Luke Frost 11 years ago

    Brilliant post. Had this exact problem, knew it couldn’t be the USB drive or the ISO. Originally tried formatting the drive through the GUI format utility built into Windows, but still didn’t work.

    Couldn’t work out what was wrong.. This worked perfectly, thanks!


  3. kirilos 11 years ago

    Thanks a ton,helped me out when i thought i was doomed.
    Great job.

  4. Mr. nice 11 years ago

    deactivate the Virusprogramms@start the Windows 7 USB/DVD

  5. Teodor 11 years ago

    Oh great! I was getting desperate with my flash drive, having tried to burn an image of windows with the Windows 7 USB/DVD tool countless times. Your method works like a charm!

  6. T williamson 11 years ago

    wow, can’t believe this solved the problem. It was a great find.

  7. Vali 11 years ago

    Thx Dude, it really was time for my netbook to get his Windows reset 🙂

  8. Corey 11 years ago

    Thank you for this… You should make this known to Microsoft because I was on the phone with tech support for 3 hours talking to multiple “experts” and none could figure out why this was happening… One of them did explain how to clean the drive and stuff which I already knew how to do anyways.. My only question was why it KEPT recorruing… They don’t know that if you use the drive in an Xbox 360, you need to go through these steps in order to get it to be used by another program created by them. Cross compatibility between Xbox & Windows sould be pretty close when handling things like “Formatting” — Anyways, thank you for finally making it clear to me what was causing it at least.. 🙂

  9. joseph 11 years ago

    thanks! this works every time i need it. i should probably bookmark this for next time.

  10. Raj 11 years ago

    Thank you for whoever made this tutorial! saved my day! God Bless you.

  11. pete w 11 years ago

    flawless victory

  12. Manikandan 11 years ago

    hey dude.. it worked.. thanks for sharing this..
    thank you very much…

  13. Fedor 11 years ago

    Thanks, it works 🙂

  14. Amnesiac 11 years ago

    This does not work for me.

    ISO is fine, USB stick is fine, disabled AVG and used the command prompt guide, everything in it’s right place but I’m still getting the same error message.

    Perhaps it’s just one of the times where I simply have to give up?

  15. Sean Peterson 11 years ago

    This article has saved me considerable head scratching, thanks!

    Haven’t dabbled in command prompt shenanigans in a fair while.


  16. Luke 11 years ago

    Hi Rene,

    i did everything, not working, so I tryed to disable my Antivir, and now: WOKRING 🙂

  17. Emceeb 11 years ago

    Thanks. Worked like a charm

  18. Jeiyaraj 11 years ago

    Greetings from Malaysia!

    Mike, I don’t know about the issues that the others were facing. I was just looking for a way to install Win 7 from a thumb drive & I stumbled across your article.

    I tried the steps u mentioned, & it worked like a charm, no dramas at all. I’ve just completed the stages up to the point where you unpack the contents of the ISO file to the thumb drive. So far, so good. Now, I’ll try to install Win 7 on my other computer with the thumb drive. I’ll update the results whether I succeed or not.

    Anyhow, Thanks for your tips up to this stage! Cheers!

  19. Hosein 11 years ago

    thanks a lot dude

  20. Domenic 11 years ago

    Thanks a lot, this works great!

  21. tanside 11 years ago

    Thanks, worked flawlessly.

  22. Sonny 11 years ago

    tnx man, I’m currently copying files to flash memory, I hope everything goes fine

  23. Stavros 11 years ago


  24. Jamal 11 years ago

    It is not working for me it stops on 97 or 98 what can i do now please help…..

  25. tom 11 years ago

    you’re awesome man

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