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. A dude 12 years ago

    ok you now saved my life 3times

    thank you again

  2. Maxien 12 years ago

    Thanks a lot!!

    However you don’t need to manually move the files to the USB. I did the command promt thing then ran Windows 7 USB DVD Download Tool again and it is now copying the files onto the USB.

    Thanks a lot though!! :o)

  3. Louis-Alexandre 12 years ago

    Thx alot. The step indicated resolved my issue.

  4. mattti 12 years ago

    Thanks very much!!!
    I was about to throw away my usb stick.

  5. Alejandro 12 years ago

    Thank you!! it works awesome 😀

  6. zhuk 12 years ago

    Great! Thank you. Very helpful information.

  7. Mr_Son 12 years ago

    Thank you very much. It works very good

  8. Samuel Mossberg 12 years ago

    This worked brilliantly, thank you!

  9. adi 12 years ago

    THANK’s a million now it is perfectly working I tried everything from quick formating to disk formating but nothing worked except yours THANKS !

  10. Auraria 12 years ago

    I am not sure when it comes to choosing the ISO file, I have no idea what to click! any suggestions?

  11. Evandro 12 years ago

    thx dude my problem was solved as you describe, very good Tutorial!

  12. Amazed 12 years ago

    Thank you so much!!!!!!111111

  13. bluescrren 12 years ago

    thx a lot!!!
    i really thought mb its my stick, couse it worked with my old one i just lost.
    but now after the preparation no problem ;D

  14. Krzaq 12 years ago

    Really great job with that article.
    Thanks a lot.

  15. H. H. Sajjad 12 years ago

    Thanks, it worked.

  16. Polo 12 years ago

    Thank you so frekkin much!

  17. tito 12 years ago

    I had this problem.. I solved this problem desactivating my avira…

  18. Douglas 12 years ago

    Thanks to Michael Pietroforte for the procedure and Rene Treffer for the tip related to Avira. It works fine to me now!

  19. sygyzy 12 years ago

    Thanks a bunch for posting this. I knew my USB stick was not defective but the download tool would not copy the files no matter what I tried. Using your instructions, I was able toa get it working.

  20. Dave 12 years ago

    Thanks bro that helped a ton 😀

  21. Pablo 12 years ago

    This post was really helpful!! thanks for your help!!!

  22. Feras 12 years ago

    thank’s. i’m so happy about this solution

  23. Ibrahim52 12 years ago

    Whoever you are buddy. I salute you for posting the MOST SMART WAY to get rid of this annoying error.

  24. AJ 12 years ago

    This works!

    I made a Google Chromium OS boot disk on my USB drive and it created half a dozen non windows partitions. Disk manager was having problems even deleting them, I got another program to remove them and used Windows to reformat it but it was the MBR that was causing problems.

  25. parabel 12 years ago

    Thank you! 🙂 Had the exact same problem, found this through Google.
    Quite lame that Windows’ disk management doesn’t offer the “clean” option in the GUI and that the WUDT doesn’t realize where the error lies.

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