Users of the Macrium Reflect 8 (the last Free version of Reflect) may find that mounting of saved image backups as a virtual drive is now being blocked by Windows 11.
Windows 10 is not affected.
Backup images can still be used to recover your system in the event of a disaster.
It’s just the mounting of backup images as a virtual drive, on a working computer, to extract particular files that is affected in Win 11.
In the latest Windows 11 update (KB5083769) Microsoft has explicitly revoked the driver (psmounterex.sys) for kernel loading via Code Integrity policy.
The driver is properly signed and still works, however Microsoft has added this driver to the Vulnerable Driver Blocklist.
Macrium are aware, but whether they will do anything about it is uncertain.
Reflect 8 is no longer officially available or updated.
There is a workaround Registry tweak, but it compromises your computer security, for the Pros and Cons of using the tweak see this thread on the Malwarebytes forum:
https://forums.malwarebytes.com/topic/335035-macrium-reflect-8-driver-blocked-psmounterexsys-cause-and-workaround/
Macrium have now made an official statement about this image mounting situation, (and a seperate VSS error):
It basically explains that what has happened only affects mounting images as a virtual drive and does not affect backup functionality.
It also points out the Reflect 8 is End-of-Life, so customers should install (and pay for) Reflect X.
I for one take that to mean that they are not currently planning to fix the mounting issue for Reflect 8 users.
Instead they are using this ‘security’ action by Microsoft’s new block as opportunity to push them to update to (and pay for) Reflect X.
However as this blocked driver issue also affects Reflect LTSC, and SiteManager 8 for image mounting functionality, and those two are not EoL, then they are probably working on a solution for those two products which might then also be applicabe to Reflect 8.
We will have to wait and see.