Overwhelmed - Macrium Reflect

Steve C · May 4, 2026

TraderGary said:
Yes, I see the problem. For the home user it isn't supported.

For the home user like me Macrium would contravene UK consumer law if they don't fix it not to mention trashing their reputation.

KevTech · May 4, 2026

Microsoft statement: April 2026 Windows security updates introduce protections to known vulnerable kernel drivers - Microsoft Support

The CVE about psmounterex.sys: https://www.cve.org/CVERecord?id=CVE-2023-43896

Bree · May 4, 2026

KevTech said:
The CVE about psmounterex.sys: https://www.cve.org/CVERecord?id=CVE-2023-43896

The thing is, Macrium addressed that CVE in v8.1.7675. It's unclear why MS block the latest psmounterex.sys.

Bug fixes and Improvements v8.1.7675 - 9th October 2023

Security Update - CVE-2023-43896

This update applies a security patch to psmounterex.sys. We advise you to install this release to ensure the security of your system.

Macrium Reflect Patch Details

KevTech · May 4, 2026

Bree said:
It's unclear why MS block the latest psmounterex.sys.

Has been proven it can still be exploited even after Macrium patched it in 2023.

Article from 2024: Exploiting Enterprise Backup Software For Privilege Escalation: Part One

Mooly · May 5, 2026

telepro21 said:
Just ran across this story. It seems pertinent to this thread---

Microsoft confirms April Windows updates cause backup failures

Microsoft has confirmed that the April 2026 security updates are causing failures in third-party backup applications using the psmounterex.sys driver.

www.bleepingcomputer.com

The story in the link suggests that this blocked psmounterex.sys driver is used by other software as well. I thought it was purely a Macrium issue. So is the driver some kind of 'generic' one? If other companies using the same driver are having issues and one of them sees fit to 'fix' the issue then would that not put pressure on the others to do the same.?

Or am I missing something here. I really thought the driver was written by and used only by Macrium.

Froggie · May 5, 2026

That article is wonky at best. MACRIUM is the author of that driver... no one else uses it. And the driver has nothing to do with VSS issues.

TraderGary · May 5, 2026

From Copilot:

Microsoft added psmounterex.sys—the old Macrium Reflect 8 image‑mounting driver—to the Vulnerable Driver Blocklist because it contains legacy kernel‑mode code that no longer meets modern Windows security requirements. The driver is properly signed, but it predates newer protections like HVCI, VBS, and modern memory‑safety rules. Once a driver is on the blocklist, Windows will refuse to load it to prevent potential privilege‑escalation or code‑execution attacks.

This only affects Reflect 8.x (including Free).Reflect X uses a new, compliant driver, so it is not impacted.

jerome · May 5, 2026

TraderGary said:
This only affects Reflect 8.x (including Free).Reflect X uses a new, compliant driver, so it is not impacted.

Macrium Reflect v.7 - v.8 use drivers psmounterex.sys and psvolacc.sys in the folder C:\Windows\System32\ - to view the Backup.
Macrium Reflect v.10 uses drivers mimkrnl.sys and psvolacc.sys (driver psmounterex.sys also present, but not used for Backup viewing)
***
Perhaps there is a programmer who can use the driver mimkrnl.sys instead of the driver psmounterex.sys for Macrium Reflect v.7 - v.8

Mitch · May 5, 2026

Hi, just for clarification, I only ever need to restore a full image backup in case of update problems. I have Macrium Reflect 8.1 paid. Is this affected by the driver issue? Mostly I restore using either the USB Rescue Media or from within Reflect. I've successfully made backups since the April Update and would be grateful for advice. Thanks.

TraderGary · May 5, 2026

Mitch said:
Hi, just for clarification, I only ever need to restore a full image backup in case of update problems. I have Macrium Reflect 8.1 paid. Is this affected by the driver issue? Mostly I restore using either the USB Rescue Media or from within Reflect. I've successfully made backups since the April Update and would be grateful for advice. Thanks.

As long as you never need to open your backup image with File Explorer and download individual files, you're just fine. Macrium image backup and restore will work as it always has.

Mitch · May 5, 2026

Hi. Thanks @TraderGary Our only need from Reflect is the ability to make or restore a full backup, either from a bootable USB Rescue Drive or to pick an image inside Reflect to restore from. We've never needed to open a backup image. Maybe some resolution will appear. Thanks again for your advice.

Mitch · May 5, 2026

Another question I should have asked please. If you need to restore a full image can you still do this either using the Macrium Boot Menu or pick an image in the Reflect program under "Restore"? Some reports say you can now only restore an image using the USB Rescue drive but not from within the Reflect program. Nothing definite on the Boot Menu. Thanks.

Froggie · May 5, 2026

Imaging & restorations work as they always have...

Scott · May 5, 2026

Mitch said:
Nothing definite on the Boot Menu. Thanks.

Just did a restore from my boot menu, no issues.

Steve C · May 6, 2026

I opened a ticket with Macrium who replied:

At this stage, I would like to reassure you that Macrium is actively reviewing the impact of these recent Windows security changes and is preparing a formal response for affected customers.

We appreciate that the current workaround is not an ideal long-term solution. Your feedback has been noted, and your case is being taken into consideration. We will ensure you are updated as soon as further information or guidance becomes available.

Mitch · May 6, 2026

Thanks @Froggie & @Scott . @Steve C , I suppose its promising that Macrium haven't outright rejected a fix. Joe Allan posted that they were investigating however another reply from their US office seemed to dispute this. Unclear how this is going to go. I only use it for full backups and restores so I don't believe psmounterex.sys affects this.

SIW2 · May 6, 2026

FDretired said:
I have overcome my frustration on problem with mounting an image with Macrium free with one time purchase of this program. Lifetime use for less than 60 dollars with a coupon. Canadian company.

Active@ Disk Image. Windows and Servers Backup Software for Windows

Active@ Disk Image can do a backup and clone the full hard drive.

www.disk-image.com

I had a look at the lite version a while ago.

just ran it in winpe, seems ok. Made a test image of only the esp partition, then had a look at it

The desktop in the pic is my fancy winpe

Doesnt seem to have anything elaborate like exclusions or delta restore.

The data recovery program from the same company is apparently good

As far as I can tell the free version does a complete image each time - cant see any option for incremental/differential

Bree · May 6, 2026

Steve C said:
I opened a ticket with Macrium who replied:

At this stage, I would like to reassure you that Macrium is actively reviewing the impact of these recent Windows security changes and is preparing a formal response for affected customers.

We appreciate that the current workaround is not an ideal long-term solution. Your feedback has been noted, and your case is being taken into consideration. We will ensure you are updated as soon as further information or guidance becomes available.

That's an encouraging sign.....

In the mean time, I have found another workaround for the few times I need to recover one or two files from an image, one that doesn't involve compromising the security of my Windows. Unfortunately I'm too tidy for Garlin's post #72 script to work, it says there's no older version to go back to.

Even the WinRE rescue media uses the block list so booting to rescue media, either USB or from the Boot Menu, won't work if it's been rebuilt recently. So I booted from an older recue USB and copied the the C:\Boot\Macrium folder from an older image. Now I can boot to Macrium from the boot menu whenever I need to browse an image.....

...I just have to remember not to rebuild the rescue media while waiting for a fix from Macrium.

SIW2 · May 6, 2026

I vaguely recall there is an option to browse to a custom.wim to create the rescue media . Any winre.wim from before the recent block list should do.

I probably still have the 26h1 march winre.wim
Build: 28000
Service Pack Build: 1701

unfortunately using 2800.1701 macrium v8 claims to have mounted the image but it hasnt

Bree · May 6, 2026

SIW2 said:
I vaguely recall there is an option to browse to a custom.wim to create the rescue media . Any winre.wim from before the recent block list should do.

Correct. It's in the Advanced options...

---edit---

I've now retrieved a WinRE.wim from before the block list was updated so I can continue rebuilding my rescue media.

Overwhelmed - Macrium Reflect

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