[OSFMount] Windows does not boot anymore after installing OSFMount

[mcls]

I installed OSFMount on my Windows system.
After a reboot, Windows would no longer boot. It said "Preparing Automatic Repair". I got redirected to a recovery environment.
The recovery environment itself provided no details about the error.
It failed to do the automatic repairs, and the recovery capabilities were also quite lacking.



The other day I tried to backup my Windows installation, but the backup software gave errors and recommended me to do a filesystem check.
I did that, but no errors were found.
I first though it was some kind of hardware failure, like the SSD failing.

Quite the unfortunate series and bad luck. Backup software fails to perform a backup and Windows fails to boot immediately after a reboot.


I continued troubleshooting.



After a lot of frustration and using a clean OS install to try to fix the problem, I was first able to get rid of the recovery environment using a hack.

Attempting to reboot afterwards gave me an error screen stating:

Your PC/Device needs to be repaired.

A required device isn't connected or can't be accessed.

Error code: 0xc000000f

Pressed Enter to "try again" according to the instructions.
I got another error screen, now with a more descriptive error:

The operating system couldn't be loaded because a required file is missing or contains errors.

File: osfdisk.sys
Error code: 0xc0000098

So I found out this driver is the one installed by OSFMount.

I deleted the driver file and was able to boot afterwards, but I immediately ran into problems.
My VPN software was no longer working, and new software installs that required drivers to be installed would fail.



System info:
Windows 10 Pro
Version: 1803
OS build: 17134.254



I was able to reproduce the problem in a virtual machine using a clean Windows 10 installation.





The software itself installed and worked fine without issues until a reboot.


Does anyone know what's causing this problem with the driver?
Is it because I'm using an older Windows 10 version?





I don't know whether it's in the scope of the forum support, but what's the best way to fix my OS issue with new drivers not able to be installed?



Hope someone can help.

[David (PassMark)]

OSFMount doesn't setup anything that gets launched at startup. So the situation seems strange. And we haven't seen or heard of this issue before either.

What type of drive are you mounting (physical or a volume, RAM disk, or file backed image)? Do you reboot the machine with the drive still mounted? Or do you dismount all the drives first?

Did you manually setup OSFMount to launch at startup?

The other day I tried to backup my Windows installation, but the backup software gave errors and recommended me to do a filesystem check

When many unexpected thing happen like this, hardware failure is a possibility. e.g bad RAM.

[David (PassMark)]

We just re-tested this in Win10 21h2 and didn't see this issue.
So maybe it is related to a specific old Win10 release.

[mcls]

We just re-tested this in Win10 21h2 and didn't see this issue.
So maybe it is related to a specific old Win10 release.

Hello, thank you for your reply.

I tested the program again and now I have the exact reproduction method.


Out of the box, the mentioned driver "osfdisk.sys" is not installed yet.
It gets installed after trying to mount an image of any kind, using the "Mount entire image as virtual disk" option.




When trying to mount using this option, I get the following error:





This is also the part where the driver gets installed on my system.



File paths:

C:\Windows\System32\DriverStore\FileRepository\osfdisk.inf_amd64_6403d31352f96c5a
C:\Windows\System32\DriverStore\FileRepository\osfdisk.inf_amd64_6403d31352f96c5a\osfdisk.sys
C:\Windows\System32\DriverStore\FileRepository\osfdisk.inf_amd64_6403d31352f96c5a\osfdisk.cat
C:\Windows\System32\DriverStore\FileRepository\osfdisk.inf_amd64_6403d31352f96c5a\osfdisk.inf
C:\Windows\System32\DriverStore\FileRepository\osfdisk.inf_amd64_6403d31352f96c5a\osfdisk.PNF
C:\Windows\System32\drivers\osfdisk.sys

Anyway, this was the incorrect option for mounting my disk image.
I did not know which option to use at first.


So I used the "Mount partitions as virtual disks" option instead and this works fine without any problems.
Using this option, no driver seems to be installed to the system.
I confirmed by mounting/dismounting the image and rebooting the system multiple times


Could you check this again and confirm that option indeed installs the "osfdisk.sys" driver?

[David (PassMark)]

A device driver file called osfdisk.sys is definitely used by OSFMount. If you right click and look at the properties, you can check the digital signature to make sure it is our file.


But the file is only used while OSFMount is running and you have a physical disk being emulated. If you reboot the machine the file should not be required or used during boot.

Just because there is a .sys file in the Windows folder, doesn't mean it is currently in use.

[mcls]

A device driver file called osfdisk.sys is definitely used by OSFMount. If you right click and look at the properties, you can check the digital signature to make sure it is our file.


But the file is only used while OSFMount is running and you have a physical disk being emulated. If you reboot the machine the file should not be required or used during boot.

Just because there is a .sys file in the Windows folder, doesn't mean it is currently in use.

I confirmed the digital signature was OK.


Using OSFMount V3.1.1002, the physical disk emulation did not work at all, so no drive was mounted.
But Windows still failed to boot afterwards.


I found older versions V3.0.1000, V3.0.1006, V3.1.1000 and V3.1.1001 which seem to work fine with Windows 10 version 1803, so I will use one of these instead.


The incompatibility with Windows 10 1803 starts with v3.1.1002 which is the current latest version.

[adam27]

Created an account to confirm this issue on windows 10 LTSC(v1809)

Installed OSFMount 3.1.1002 to mount/modify a disk image, however any file transfers to the disk failed and locked explorer when using logical emulation, physical emulation reported that the osfdisk.sys driver wasnt installed. Checking device manager showed the osfdisk virtual adapter failed to load due to a driver issue. I thought it was a driver signing issue as mentioned in the known issues section so i restarted to disable driver verification.

Exact same issue is OP, windows failed to boot and got stuck in an automatic repair bootloop. *something* with the windows bootloader system partition got trashed bootrec /fixboot failed with access denied, /scanos and /rebuildbcd failed to find the windows install. I eventually fixed it with bcdboot F:\Windows /l en-US /s W: /f ALL (for anyone who runs into the same issue, replace F: with the windows install drive letter, and W: with your EFI boot partition letter after assigning it a letter in diskpart)

Rebooted again and got the same error as OP

The operating system couldn't be loaded because a required file is missing or contains errors.

File: osfdisk.sys
Error code: 0xc0000098

deleting the driver allowed me to boot into windows again. I havent ran into any other issues *yet* like OP did but I'm posting this a mere half hour after getting 10 to boot again.

[David (PassMark)]

Windows 10 LTSC 2019 (Win 10 version 1809) is pretty old now, and obviously missing many years of patches and upgrades. We'll see if we can find a copy of it for testing.

[adam27]

Windows 10 LTSC v1809 is supported by MS until 2029 and receives security/quality updates until then, It just doesnt receive feature updates by design. If you cant find a copy of v1809 enterprise or maybe sever 2019 would be the closest equivalent

[Simon (PassMark)]

We were able to reproduce the issue. Made some changes which should address this:
https://www.passmark.com/downloads/t...g_20240221.exe
Let us know how it goes

[adam27]

Appears to be fixed, device driver loads fine and i am able to read/write files in both logical and physical drive emulation mode and format the raw disk image. Made a backup of my windows drive just in case i run into an issue though.