Fix: Unable to Mount ISO on Windows 10/8/7

One of the main feature of Windows 10/8 is the ability to mount ISO image without the help of third party application. We often use this feature because large software downloads like Office or Visual Studio and sometime games too, are available for download in the .ISO format. In such cases, rather than burning to disk and running it, it becomes a lot easier to just mount it and run it just like a disk.

Unable to Mount ISO image on Windows

Last week my client ran into this issue where he was unable to mount ISO image on Windows 8. The mount option itself is missing. My initial thought was that he may have messed up with some of the system files. So I ran SFC /SCANNOW or System File Checker. To run SFC /SCANNOW:

  • Press Win + X
  • Click on “Command Prompt (Admin)
  • Type in SFC /SCANNOW

I rebooted the system and tried to mount the ISO image again. But still I could not see the option. Then I noticed that he had installed a 3rd-party application to Mount the ISO image – called Virtual Clone. But the version he had installed was unsupported for Windows 8. When I tried to upgrade it to new version, it failed. I used a free uninstaller software Revo Uninstaller to remove it completely and rebooted the system. Then I tried to mount again – but still no luck!

So I went to Default Programs to check if the file associations were set correctly. To go to Default Programs go to a Windows UI screen and type in Default Programs  and press Enter.

Unable to Mount ISO on Windows 8

I clicked on “Associate a file type or protocol with a program” and looked for ISO but I couldn’t find it.

Finally I decided we may need to run a Repair Install or Refresh Windows 8. But before doing a repair I thought of trying something. I went into the Windows Registry and checked the Shell entries for:

HKEY_CLASSES_ROOT\.iso\OpenWithProgids

It was still being associated Virtual Clone instead of Windows.IsoFile.

The 3rd-party software had failed to uninstall correctly, and even Revo was unable to uninstall it fully!

I had Windows 8 installed on my laptop so I went and extracted all the Shell keys related to ISO from different locations and merged into one. I then imported that key in his registry and rebooted the system.

It worked!

Download Registry Fix

I am now, able to see the mount option and it works perfectly fine. I have attached the registry file here so in case if you run into similar problem you can just import this registry key. You can download the file to fix this problem by clicking here.

Do always create a system restore point first, before making any changes to your system. 

Posted by on , in Category Windows with Tags
Shyam aka “Captain Jack” is a Microsoft MVP alumnus and a Windows Enthusiast with an interest in Advanced Windows troubleshooting. Suggestions made and opinions expressed by him here are his personal one's and not of his current employers. He blogs at captaindbg.com.