Issue with mounting new ISO files from TechNet in Windows 8 and Windows 8.1 Preview

posted in: Blog | 72

Microsoft Windows 8.1 logo
Yesterday, I downloaded Windows 8.1 Enterprise Preview, so I could install it on my Surface Pro. I went to TechNet, downloaded the ISO, everything seemed fine, but then I tried to mount the ISO.

Mount ISO Windows 8 8.1

This is the error that I received:

“Sorry, there was a problem mounting the file.”

Mount ISO error Windows 8 8.1

I thought that it might have been my download that was corrupt, so I downloaded it once again, tried to mount it, but still with the same error. My conclusion was that there was something wrong with the ISO from TechNet or that there was some bug in mounting the file in Windows 8.1 Preview.

Today, I downloaded the Windows Server 2012 R2 ISO from TechNet, and tried to mount it on another computer with Windows 8. Same problem as yesterday!

After some Googling around, I found a couple of other people having the same issue. Apparently, there’s a flag that is set on the ISO file, which makes it unmountable.

The solution:

  • Make a copy of the ISO file, place it anywhere and then mount it

I’m not sure why this happens, but if you have any more information about this issue, please leave a comment!

72 Responses

  1. Nathan Maluk

    Hi everyone. Had this problem. An ISO just needs to be Unsparsed, then you can mount the ISO. I have one iso, it’s weight is 225 GB so I won’t to copy it in another location just to be able to mount it 😀
    A fix is very simple for any ISO, just add this reg file and right click your ISO, select Remove Sparse and just mount it! 😀 Voila! Now you haven’t to copy your ISO, just use this simple fix.

  2. OMG it works! wasted time re-downloading 4GB ISO file…

  3. Thanks, Daniel. Great post.

  4. Actually, big thanks to Nathan Maluk, too. The Unsparsing works as well.

  5. I am trying to mount an ISO file of MS Visual Studio 2013. I have tried what you suggested above and it is not working. I have a Surface Pro 3 running Windows 8.1

  6. As others have said, double clicking the iso does actually mount it. In my case, on a drive marked CD (on a Surface??). Then just run the setup.exe. Not sure removing the SD card makes a difference although that used to fix things when V8 preview was released, so things haven’t moved on much..

  7. OMG! It actually worked! Unsparsing?! Nathan Maluk, Thanks!!

  8. Ronnie

    Took me some figuring out why this solution at first didn’t work for me. For some reason all the iso’s where read-only. After I remove the RO attribute the remove sparse works perfectly.
    Now I’m wondering, does anyone know how to use the remove sparse reg key as such that it first automatically removes the R using: ATTRIB -R “%1” before the fsutil command, All-in-1 nice remove sparse button?

    Tx in advance, Ronnie

  9. Hi folks, unfortunately, it does not work for me – copying ISO to another location MUST BE copy not MOVE, works but that unsparsing thing does not. any hints on that?

  10. qwerty

    Nathan Maluk, thanks a ton!

  11. I think I have a possible reason. I took your article and considered what “flag” might affect this. I just imagined that an ISO should always be read-only to make sense. Maybe it’s looking for that. I set the “read-only” flag in the properties for the files in question, and …

    Bam!! It mounts with no errors. Thanks to you I can now end this headache.

  12. May I suggest a new solution. Here is a piece of code and application which may solve the problem. It sets the sparse flag to 0 (zero). This thing worked for me perfectly.

  13. nishad

    thanks Daniel. Keep the help coming!:)

  14. Colonist

    Thanks ! It’s works ! funny joke windows 😀

  15. kalashnikov

    nah, none of the above worked. still getting the unable to mount image message.

    thanks microsoft, keeping our lives hard as usual….

  16. invegat

    I never got en_visual_studio_enterprise_2015_rc_x86_dvd_6649702.iso 3,994,929,152 bytes to Mount on Windows 7 or from the VirtualBox shared folder of Windows 10 Enterprise Insider Preview, but copying the file to a local directory in Windows 10 worked. I knew the ISO file was good because the SHA1 Hash generated by Get-FileHash matched.

  17. Can somebody please explaine how set up the regedit fix. I have never worked with Regedit before. I’m doing something wrong but I don’t know what. When I right click the popup menu shows Remove Sparse. But when I click it I get a question which program to choose to open it. When I select Windows Explorer I get the mounting error message.

    Thanks in advance.

  18. Charlie Clay Jr

    Are you flipping kidding me?

    After 90 mins of jacking around with this. Copying and mounting really worked? Sheesh!!!

    Thanks anyway.

  19. hey guys, i found something rather interesting as I myself was experiencing this problem. right click on the ISO file, go to properties. just beneath the “read only” option, check for something which says ” this file has come from another computer, to protect….”; there is also an “unblock option in front of the note. uncheck read only, and click on unblock. apply, and see what happens. worked for me. hope the same for you guys

  20. If you mount the file from your desktop there is no need to mount from image file

  21. Thanks for the solution..

  22. his sparse attrib problem happens all the time with downloaded ISOs for me.

    Put this in a batch file and drag-and-drop the target file onto it (with Windows Explorer). Et voilà.

    fsutil sparse queryflag %1
    fsutil sparse setflag %1 0
    fsutil sparse queryflag %1

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