One of the problems that a Windows 10 user may facing when mounting an ISO image file with built-in Windows 10 tools is an error that the ISO file could not be mounted: Make sure the file is an NTFS volume and isn’t a compressed folder or volume.
In this manual we’ll take a look on how to fix the “Couldn’t Mount File” error when mounting an ISO image in Windows 10/8.1.
Most often, this error occurs for iso files that are downloaded using the torrent clients, which can set the SPARSE attribute for the file.
Note. An ISO image can return such error when you are trying to use it in Hyper-V on the virtual machines of the second generation (Gen 2 VM).
The easiest way to fix a problem is to make a copy of your ISO file, the sparse attribute is automatically reset.
You can also manually remove the sparse attribute from an ISO file using the command line.
- Run the Windows PowerShell console with administrator privileges;
- Using the following command, check whether the sparse attribute of your ISO file:
fsutil sparse queryflag “C:\iso\windows10.iso”;
- If the previous command returned “This file is set as sparse”, you can remove the attribute using the command:
fsutil sparse setflag “C:\iso\windows10.iso” 0;
- The message “This file is NOT set as sparse” should appeared.
In most cases, the described steps are sufficient to fix the problem and the error “Make sure the file is an NTFS volume” no longer appears when connecting this ISO image.
If the actions with the sparse attribute have no effect on fixing the problem, there are additional ways to find its cause and mount an ISO image.
First, check (as mentioned in the error message) – whether the volume or folder with this file or the ISO file itself is compressed? To do this, you can perform the following actions:
- Open your drive properties using File Explorer. Make sure that the Compress this drive to save disk space checkbox is not selected;
- To check the folder and the iso file itself, open the properties of the folder (file) in the same way and in the Attributes section click Advanced. Make sure that the option Compress contents to save disk space is not enabled for the folder (iso file).
Note. By default, in Windows 10 the compressed folders and files display an icon of two blue arrows, as on the screenshot below:
According to some reports, the problem can also be caused by the update KB4019472, released in the summer of 2017. If somehow you installed it just now and got an error, try to remove this update.
In order to avoid this problem in the future, we recommend you to enable the option “Pre allocate all files” in your torrent client. In uTorrent, this option is in the program settings. On the General tab check the box Pre-allocate all files and save changes by pressing OK.
After activating this option, you can try to re-download the problem file, after which the problem with its mounting and launch should disappear.