Does Mac open dmg file no mountable file error constantly appear? As a matter of fact DMG file is treated as physical disk that automatically mount as .dmg file normally whenever you double click on it. However sometimes it fails to mount and displays unexpected error message stating as Mac open dmg file no mountable file error that needs to be sorted out immediately. So you can mount DMG file manually as well. In order to do so you need to use built in tool of OS X.
Steps Which Need to Be Followed for Manual Mounting of Disk Image
- Go to Disk Utility from Applications list which be in Utilities folder.
- Now click at "Mount" from the top then select .dmg file which needs to open. After mounted it would appear at the desktop in the form of an icon.
- Then double click in icon and open it.
Hope by using above mentioned steps you would fix Mac open dmg file no mountable file error. Unfortunately if the issue still remaining case one should go with formating hard drive again then after reinstall fresh OS X from the original disk. And for regaining missing Mac data try Mac Data Recovery Software without waiting too much now!!