Can't Mount ISO Files Natively Anymore

l0mars01 · Oct 16, 2014

My OS formerly mounted ISOs with an Enter or double-click in File Explorer.
Now I get an error

Most remedies from a quick Google search don't apply:

the ISO files don't have a sparse flag set , so
Code:
```
fsutil sparse setflag filename 0
```
does nothing, copying does nothing
the native Windows handler is already set as default, hence the above error
utilities like 7-zip can open these files
non-native ISO mounters can mount these files
Code:
```
sfc /scannow
```
didn't help

Code:

[FONT=Verdana]dism /cleanup-image /online /restorehealth[/FONT]

didn't help

the OS was installed yesterday
Microsoft Security Essentials isn't the issue (I just checked a virtual machine running only my version of the OS and MSE: it can mount ISOs); MSE is necessary since the server edition doesn't include a built-in AV

A week ago, I thought it was time to do a fresh install of Windows in case I had corrupted the ISO mounting driver somehow.
I got the updated install media from Microsoft (2012 R2 Update, the server edition 8.1 Update), wiped the hard drive, installed it, and fully updated it, expecting it to work.
To my shock, it does not.
I'm beginning to think an update or a driver is at fault here, since I haven't installed anything unusual.

If anyone can solve this problem for me, then it would be utterly heroic.
It's been bugging me a while.

Brink · Oct 16, 2014

Hello mars,

You might see if downloading and merging the .reg file for the ISO option in the tutorial below may be able to help. It will restore the default associations and registry entries for ISO files.

http://www.eightforums.com/tutorials/8486-default-file-associations-restore-windows-8-a.html

l0mars01 · Oct 16, 2014

Standard user account can no longer mount ISOs natively

Thank you!
My administrator account can mount ISOs!
I wasn't sure until I switched to an administrator account.

New problem: my standard user account still can't mount them.
It requests administrator credentials and still does the "Sorry" business from before.
It's probably a security permissions issue or a profile-specific issue.
I tried importing your registry entries on a standard user account and got an error.
Only an administrator can do it entirely.

A virtual machine running only a fresh install of my OS does allow standard users to mount ISOs after they enter administrator credentials.
It's definitely not the default permissions.

The only permissions I'm aware of changing are disabling "Enforce password complexity", giving everyone permission to shutdown the computer, and allowing shutdowns without logging in.

I'm still happy the administrator can mount ISOs now. That's progress!

Brink · Oct 16, 2014

Are the ISO files located in a folder that the standard user doesn't have access allowed by chance?

l0mars01 · Oct 16, 2014

They're in either the standard user's folder or "Public" user's folder.

Brink · Oct 16, 2014

As a test, copy the ISO file to anywhere, then try to mount it afterwards.

l0mars01 · Oct 17, 2014

Thanks for looking into this.
It still fails to mount like before.

Brink · Oct 17, 2014

Just to make sure, you did copy (right click "Copy") and "Paste" the ISO and not drag and dropped or any other method?

l0mars01 · Oct 17, 2014

I pressed CTRL as I dragged and released.
The UI tells me this performs a copy as I do it.

If it helps, I can fetch you some entries from the Event Viewer.
I was looking there before, but I didn't know what to look for (source name, log name, etc).
I was also thinking of using Process Monitor to get some clues, but that dumps a ton of information.

PS Sorry for the delay. I had to take a snooze.

David Bailey · Oct 17, 2014

Instead of---

Try---

Dism /Online /Cleanup-Image /RestoreHealth

Then run sfc /scannow

l0mars01 · Oct 18, 2014

I think that's what I did, and I recalled the command incorrectly when I wrote about it.
I'll correct that shortly.
Just in case, here's the output.

PS C:\Windows\system32> dism /cleanup-image /online /restorehealth

Deployment Image Servicing and Management tool
Version: 6.3.9600.17031

Image Version: 6.3.9600.17031

[==========================100.0%==========================]
The restore operation completed successfully. The component store corruption was repaired.
The operation completed successfully.
PS C:\Windows\system32> sfc /scannow

Beginning system scan. This process will take some time.

Beginning verification phase of system scan.
Verification 100% complete.

Windows Resource Protection did not find any integrity violations.

Unfortunately, ISO mount still fails for my standard user.

I really want this to work.
Can I provide you any more information?

David Bailey · Oct 18, 2014

Go out & buy a full retail version.
Then you'll have no problems.

I'm not rich.
I spent some money & have 8.1.1 Pro WMC installed & working good.

Just my 2¢.

l0mars01 · Oct 18, 2014

I think you misunderstood: it is a full retail version.
"User Accounts" offers 2 types of accounts:

Administrator
Standard

Both types can mount ISOs on a completely fresh install of my OS without updates. (I've checked on a virtual machine.)
Brink helped me get Administrators mounting ISOs again.
My standard account still can't.

l0mars01 · Oct 19, 2014

Development!

I traced a possible cause of the problem, but I don't know what to do about it.
The community's insight here would be extremely valuable.
With Sysinternals Process Monitor capturing data, I attempted to mount an ISO, then dove through the results.
Here's the log: View attachment Logfile.zip
I'm terribly inexperienced, so please examine it if you think you can get better insights.

In a way, it shows me attempting to mount the ISO as a standard user, then a request for credentials, and an attempt to mount the ISO as the administrator I selected (named "Elevated").
Here's where I see it clearly go wrong

It attempts to act on path "C:\Users\Elevated\Downloads\temp\Windows XP x64.iso" when my ISO is located at "C:\Users\Luis\Downloads\temp\Windows XP x64.iso".
"Elevated" is the administrator I select when the UAC requests permission.
Windows is replacing the original user's profile path with the administrator's.
It's no wonder it fails to mount my ISO: it's going to the wrong location!

Just to check, I made a hardlink from "C:\Users\Elevated\Downloads\temp\Windows XP x64.iso" to "C:\Users\Luis\Downloads\temp\Windows XP x64.iso" and tried mounting "C:\Users\Luis\Downloads\temp\Windows XP x64.iso" again.
Sure enough, it "works".

tl;dr Windows is mangling an ISO's path when a non-administrator attempts to mount.

What can be causing this, and how do I fix it?

kuki · Mar 14, 2015

I have the same issue right now.

I think some of my old images work as expected, the new ones, downloaded AFTER I did complete win 8.1 reinstall ( a few days ago). Moving them to external hard drive is a king of semi-solution, because then they do work.

I0mars01 - did you solve that issue?

edit:
Tried different approaches that I have found searching through web, but nothing helped. Just reinstalled windows 8.1 proffesional x64 and guess what? Nothing has changed, fresh windows install, no drivers , no updates and it fails to load ISO.
Moreover, I do have problems with burning those images to my external USB drive. Some images work, some do not, All of them work when copied to external HDD.

l0mars01 · Mar 15, 2015

No, I never solved it, and our experiences match.
The best solution I know is no solution at all, but workarounds: either

log in as an administrator (which defeats the purpose of security restrictions, right?), or
keep ISOs off paths under the logged-in user's profile.

Then switching security contexts (when you choose an administrator in the UAC) for a mount operation won't mangle the ISO file's path:

In the former case, you don't switch security context as you're already an administrator;
in the latter case, the file-path is safe from profile changes that come with switching security context: i.e., file-path transformations from C:\Users\standardUser to C:\Users\administrator do nothing to paths lacking C:\Users\standardUser

However, I've never reported this problem to Microsoft. They might properly fix this if they knew.

As far as I know (I've never had to try this), clearing the sparse flag

Code:

fsutil sparse setflag [I]filename [/I]0

addresses the same problem copying does.
You can check for the sparse flag in the file's attributes:

GUI: File properties, Details tab, Attributes, P
command-line:
Code:
```
fsutil sparse queryflag [I]filename[/I]
```

If you move the ISO off the logged-in user's profile (or log in as an administrator), and clear any sparse flags on it, then it should mount.

altae · Mar 15, 2015

Why don't you use a third party app to mount Isos? I have always used Daemon Tools (the free version) and so far it has never let me down.

l0mars01 · Mar 15, 2015

Update

I spoke to a tech support agent, and she points this out to me:
If you open C drive in Windows Explorer and navigate to an ISO file under your user profile, then it opens!
You can't start from your profile (where Windows Explorer starts) and navigate straight to your ISO.
This appears to be a Windows Explorer bug.

l0mars01 · Mar 15, 2015

Because native mount is THE PATH TO REDEMPTION. 3RD PARTY APPS HAVE BEEN PLACED HERE TO TEMPT THE FAITHLESS. DO NOT GIVE IN!!! THE MIGHTY NATIVE MOUNT HAS SPOKEN!!!

But seriously, because it's broken and I want to fix it, which is pretty much the whole point of this board. Sure, I'll workaround it (with ImDisk) until I learn how to fix it, but the moment I learn how, I'll still fix it.

Zen · Mar 17, 2015

I have seen a few fixes to this problem in this thread ... I know the thread is a little aged but since it is still referenced on a google search I feel I should add some technical information to this thread that should resolve the issues ...

Your ability to not mount the .iso image is caused by Microwhat? file security system ...

how to make .iso's mountable ...

There are a couple of things that might occur when you right click on an .iso file ...
1. there is no mount option
2. there is a mount option but when you click on it it gives you an error about some lack of ability of microsoft developers that prevents you from performing a valid function ...

here are a couple of methods to fix either or both of the problems above ... users choice ...

1. simple and easy ... get 7zip it opens the archive which should allow you to install whatever ... (it is free and easy to use and should not contain any malware)

2. right click on the .iso file > select Properties at the bottom of the list > Select the Details tab at the top > Click the link at the bottom that says ( Remove Properties and Personal Information ) > a new box will pop up with two options at the top ... the first default option is the best option but both options work ... > select ok ... when it is done you will see a new file ... "Original file nam.iso - copy" right click on the one that says copy ... you will now have the option to mount the file even if you did not have the option before ... mount and enjoy ...

Can't Mount ISO Files Natively Anymore

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