Windows 10/8 is the ability to mount ISO image without using any third party application. I have get an ISO disc image file about 20 GB in size in my downloads folder, but couldn’t mount it to the default iso drive. It just pops up the error message “>Make sure that the file is in an ntfs volume and isn’t in a compressed folder or volume.” Others on my external hard drive are also refused to Mount. If I right click on it and select Open with Windows Explorer and still get the same error. Everything worked fine before and the file is really located is NTFS.
This is a bug in Windows 10 and the security update KB4019472 causes the issue. You can remove the culprit by the way.
* Type update in start menu or Cortana search box, and press Enter.
* When you see the view installed updates, locate the KB4019472 update and uninstall it completely.
Then everrything will be normal. However, the Windows 10 always keep downloading and installing the last security update to system. You could try any of other methods to get rid of that.
* Move the iso to another local disk and you are able to mount the file. Moving it back again to the original location also does the trick. After I move the file to my desktop, the function works out.
* The other software such as Daemon tools or Power ISO does the good job. Daemon Tools can easily mount an image on their Virtual CD/DVD Rom.
* The winRAR archiver also can help you resolve the problem and it requires enough free space.
Right click on the ISO file, select Open With > WinRar, and extract all files in folder. I extract the files as big as 50gb and it works well.