Windows 8 can mount the ISO files without the need of an external third-party software, but apparently some users have reported a problem with this feature. Windows throws an error message that says “You don’t have permission to mount the file”, when an ISO image is mounted.
According to Microsoft, this problem reported in Windows 8, Windows 8.1, and Windows Server 2012, arises due to 3 specific reasons known as of now, firstly, a USB media reader device is plugged-in to the computer, secondly, a
Removable media is connected to the computer, or finally, an .iso file that you are trying to mount is a sparse file. You are probably doing any of these 3 actions, for Windows to throw the error. Don’t worry, there is a fix to this issue, it’s an easy one!
First thing you need to do is figure out whether the ISO file that you have is a Sparse file. To do that, simply right-click on the ISO file and click “Properties”, then click “Details”. Now check the Attributes line, if it is letter “P”, then it implies the ISO image is a sparse file. If it is letter “A”, then the file is not a sparse file.
For sparse file scenarios follow the method 1 to fix the problem.
METHOD 1: Apply when an ISO image is a Sparse file
Rename the ISO image to a different name, to remove the sparse attribute. You can now mount the ISO image.
METHOD 2: When you have plugged-in a USB device to your computer
For those who have ISO image that is not a sparse file, try to remove all the USB devices like Media reader, USB flash drive etc. Now try to mount the ISO image, it should get mounted. You may now connect all other USB devices. In this fix we are actually keeping the lowest letter to mount ISO, apparently, that is the solution to the problem. The ISO file might not work, if it has an assigned drive that follows other drives.