Issue: You receive an error “Couldn’t Mount File” when attempting to mount an ISO file in Microsoft Windows 8.1.
Cause: When you download an ISO file to an NTFS volume, Windows may set the “sparse” attribute on the file. A sparse file attempts to use file system space more efficiently by using metadata to represent empty blocks of data. The built-in ISO mounting feature of Windows 8.1 cannot mount a file if it is sparse.
Solution: One way to correct this issue is to simply make a copy of the ISO file. The copy will have the sparse attribute off.
You can also view or change the sparse attribute of a file. To view the current sparse setting of a file use:
fsutil sparse queryflag <filiename>
To change the current sparse setting of a file use:
fsutil sparse setflag <filename> 0|1
