Reflect 8 No Longer Mounts an Image File for Windows Explorer

SIW2 · May 7, 2026

garlin said:
I've written a batch script which reverts the Vulnerable Driver Blocklist to the previous version (which doesn't block Macrium 8)

https://www.elevenforum.com/t/overwhelmed-macrium-reflect.46159/post-736027

If you want to use psmounterex in the boot media one way is to use a wim from before the updated blocklist.
I think the latest winre.wim for that would be 26100.8031 from march 2026
en-us_windows_11_consumer_editions_version_25h2_updated_march_2026_x64_dvd_a1cf6c36.iso

In the macrium media builder there is an option to browse for a custom wim

garlin · May 7, 2026

You can just mount the boot.wim and delete "\Windows\System32\CodeIntegrity\driversipolicy.p7b"

SIW2 · May 7, 2026

Should be able to delete it very quickly with 7-zip gui.

Rt click the offending file and select delete

It has gorn

Isn't it better to have an earlier version of that file than none at all ?

What happens if instead driver.stl is deleted and previous.driver.stl is renamed to driver.stl ?

Or maybe rename both of them.

driver.stl > new.driver.stl and previous.driver.stl > driver.stl

What is the effect of that ?

KB5029033: Notice of additions to the Windows Driver.STL revocation list - Microsoft Support

support.microsoft.com

Froggie · May 8, 2026

Posted today from Macrium...

Image Mounting or VSS Errors Following Recent Windows Updates

Image browsing and VSS snapshot creation issues following Windows update KB5083769 with psmounterex.sys image mounting driver added to Vulnerable Driver Blocklist.

kbx.macrium.com

FDretired · May 8, 2026

This my solution - Macrium 8 free

1) Start->right click ->Device manager -> network adapters-> disable wireless adapter (I use wireless adapter)
2) Start->Settings->device security->core isolation details->Microsoft vulnerable block list-->off
3)Restart
4)Mount Macrium image and retrieve files or folder
5) undo #2
6)Restart
7)Undo #1

Steve C · May 8, 2026

FDretired said:
This my solution - Macrium 8 free

1) Start->right click ->Device manager -> network adapters-> disable wireless adapter (I use wireless adapter)
2) Start->Settings->device security->core isolation details->Microsoft vulnerable block list-->off
3)Restart
4)Mount Macrium image and retrieve files or folder
5) undo #2
6)Restart
7)Undo #1

Nuking your security is not an effective solution!

garlin · May 8, 2026

My suggested fix was to roll back the driver blocklist to the previous version. So you're mostly protected.

FDretired · May 8, 2026

Steve C said:
Nuking your security is not an effective solution!

I am disconnected from the internet when the security is nuked.

Addendum. I did further reading with the help of co-pilot. The risk is not totally mitigated if I am not connected to the internet. However, it is minimal if I just mount the image retrieve some files and do nothing else.

pokeefe0001 · May 8, 2026

Steve C said:
Unless Macrium restores the functionality, provides a free upgrade to Reflect X, or refunds the licence cost, you are in breach of contract for failing to supply the product as advertised.

I know nothing about British law, but I suspect Paramount is under no obligation to provide support for a product that is beyond its EoL date, and I'm sure they will not offer free upgrade to Reflect 10. However, the Macrium Reflect 8.1 LTSC (Long Term Service Channel) is supported through 2027 so some kind of remediation is going to be available to some 8.1 users. Hopefully that will be made available to all 8.1 users

SIW2 · May 9, 2026

garlin said:
You can just mount the boot.wim and delete "\Windows\System32\CodeIntegrity\driversipolicy.p7b"

error message:
The operating system couldn't be loaded because code integrity failed to initialize

SIW2 · May 9, 2026

For now the solution seems to be an earlier winre.wim.
The one from 25h2 march installation media is the most recent that works with macrium mounting as far as I can tell

Steve C · May 9, 2026

pokeefe0001 said:
I know nothing about British law, but I suspect Paramount is under no obligation to provide support for a product that is beyond its EoL date, and I'm sure they will not offer free upgrade to Reflect 10. However, the Macrium Reflect 8.1 LTSC (Long Term Service Channel) is supported through 2027 so some kind of remediation is going to be available to some 8.1 users. Hopefully that will be made available to all 8.1 users

Under UK law, specifically the Consumer Rights Act 2015, digital products such as Macrium Reflect 8 must remain as described, fit for purpose, and functional for a reasonable period, which for paid software is generally interpreted as up to six years — the standard limitation period for breach‑of‑contract claims. Even if Reflect 8 is end‑of‑life, Macrium is still legally obliged to ensure that core, advertised features continue to work for a reasonable time after purchase; they cannot rely on EOL status to avoid responsibility. If a key feature like image mounting stops working due to Macrium’s failure to maintain compatibility, the product no longer matches its description, and the customer retains the right to a repair, replacement, or refund for up to six years from the purchase date.

garlin · May 9, 2026

SIW2 said:
For now the solution seems to be an earlier winre.wim.
The one from 25h2 march installation media is the most recent that works with macrium mounting as far as I can tell

March 2026 image will have the previous version of driversipolicy.p7b embedded in the WinRE.wim.

You can copy the old file from WinSxS:

Code:

C:\Windows\WinSxS\amd64_microsoft-windows-c..egrity-driverpolicy_31bf3856ad364e35_10.0.26100.7623_none_4fe4046d9426924f\driversipolicy.p7b

SIW2 · May 9, 2026

garlin said:
March 2026 image will have the previous version of driversipolicy.p7b embedded in the WinRE.wim.

You can copy the old file from WinSxS:

Code:

C:\Windows\WinSxS\amd64_microsoft-windows-c..egrity-driverpolicy_31bf3856ad364e35_10.0.26100.7623_none_4fe4046d9426924f\driversipolicy.p7b

Boots up ok but macrium doesnt mount, psmounterex not working.

will try with 7623 driver.stl files as well

SIW2 · May 9, 2026

sadly macrium mounting doesnt work with with 7623 driver.stl files as well

SIW2 · May 9, 2026

also tried swapping the code integrity folder from 26100.8031 into 2800 winre. Refused to boot.

might work in a different 26100 or 26200 winre for example from the april 26 25h2 media.

SIW2 · May 10, 2026

could use 26100.8031 wim or earlier.

Overwhelmed - Macrium Reflect

26100.8031 works macrium mounts Information for Image 1 ----------------------- Index: 1 Name: Microsoft Windows Recovery Environment (amd64 Description: Microsoft Windows Recover Environment (amd64) Directory Count: 4601 File Count...

www.elevenforum.com

idgat · May 10, 2026

Microsoft has decided to "blacklist" psmounterex.sys as a security risk

Solution ...
Open the regedit in admin mode, navigate to
HKLM\SYSTEM\CurrentControlSet\Control\CI\Config > VulnerableDriverBlocklistEnable and modify the key from 1 to 0
Reboot, mount the image, when done then unmount image, change the key back from 0 to 1, reboot

Take that, Microsoft!

But the usual caveat applies, image your system before trying anything

Slavic · May 10, 2026

Why the Microsoft's decision of blacklisting was correct:

1) Information about psmounterex.sys on the resource Living Off The Land Drivers (LOLDrivers.io):

0f64bf7a-2ef2-45ea-af7d-4e7c87d98777

psmounterex.sys Description Northwave Cyber Security contributed this driver based on in-house research. The driver has a CVSSv3 score of 8.8, indicating a privelege escalation impact. This vulnerability could potentially be exploited for privilege escalation or other malicious activities. UUID...

www.loldrivers.io

2) Investigation of vulnerability and demo exploit by Northwave cyber security (in two parts):

Exploiting Enterprise Backup Software For Privilege Escalation: Part One

northwave-cybersecurity.com

Exploiting Enterprise Backup Software For Privilege Escalation: Part Two

northwave-cybersecurity.com

From the conclusion:
We developed proof-of-concept exploits for each vulnerability and shipped these, along with a root cause analysis, to the software manufacturer. [...] The manufacturer quickly fixed the bugs...

Now we users can hope that the fixed version of this driver will be publicly available when Microsoft will check its security. At least, for Macrium Reflect 8.1 LTSC.

Josey Wales · May 10, 2026

I do not have a problem mounting an image using Mr 8.1 on my wife's PC.

Reflect 8 No Longer Mounts an Image File for Windows Explorer

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