Macrium 8 free, windows 10, mounting backup gives error "location not available" and "drive:\ is not accessible. The parameter is incorrect"

[GBT]

So a possible hybrid issue but i wanted to see if anyone else has any ideas.

The image was created on PC1 which was a windows 10 PC with macrium 8 free.

The image was saved to a synology NAS drive different user id & password.

I have accessed the NAS image with PC1, prior to converting to win 11, to copy some files out to my PC so I know the image is good.

PC1 died shortly afterwards and rebuilt as a windows 11 PC (not my choice!).

I now know that win 11 is blocking macrium so I use my laptop, win 10, to load macrium.

Win 10 laptop has different user id & password to Win 11 PC and the NAS.

I can see the raw image file and Macrium shows the different partitions that are available in the image.

I can select the partition i want and choose a mount drive from the macrium drop down list.

macrium shows a progress window. Windows shows the mapped drive appear in explorer.

When i click on the drive to look at the contents I get the error message popup "location not available" and "drive:\ is not accessible. The parameter is incorrect" regardless of what drive letter i assign.

I presume the error is not because i dont have access to the NAS from my win 10 laptop - the fact that I can see the image file and partitions suggests I have the necessary access.

Macrium is functioning as expected so it suggests possibly a permissions issue between the user ID used to create the image and the user ID of my laptop. I don't know/can't find anything that says macrium maintains the original login credentials used to create the image nor can i find any way to specify the login credentials to load the image to test this. (based on the fact that my original mount of the image was from the pc that created the image - PC1)

At the moment I have several images sat on the NAS created with Macrium free 8 that predate the windows 11 block of the .sys file that i can see are there but cannot access.

Help!

 

[ChatGPT]

Most likely cause​

GBT, this does not look like a NAS or user-account permission problem.
Macrium images do not retain the Windows login credentials used to create them. The Synology credentials only provide access to the .mrimg file. NTFS permissions inside the image are separate, and Macrium’s Enable access to restricted folders option is designed to handle images created under another Windows account. A permissions problem would also normally produce Access is denied, rather than The parameter is incorrect.
Since the Windows security updates released on April 14, 2026, Microsoft may block Reflect 8’s psmounterex.sys image-mounting driver. Macrium confirms that the backup can appear to mount and receive a drive letter while its contents remain inaccessible. Backup verification and full-image restoration are not affected. (kbx.macrium.com)

1. Confirm whether the driver is blocked​

1. Attempt to mount the image again so the error is reproduced.
2. Open Event Viewer.
3. Navigate to:
   Applications and Services Logs > Microsoft > Windows > CodeIntegrity > Operational
4. Look for Event ID 3077 at the time of the mount attempt.
5. Check whether it names psmounterex.sys.

Event 3077 is the primary enforced Code Integrity block event.
Also run winver on the laptop and confirm that it really is Windows 10. Macrium’s currently published affected list specifically names Windows 11 24H2/25H2 and supported Windows Server versions, so a genuine Windows 10 installation without Event 3077 may have a different mounting-driver problem. (kbx.macrium.com)

2. Rule out NAS and image-chain problems​

If there is no psmounterex.sys Event 3077:

1. In Reflect, select the backup and run Verify Image.
2. If it is an incremental or differential backup, ensure the full image and every required preceding image are present.
3. Copy the complete backup set from the NAS to a local NTFS disk or USB drive.
4. Mount the local copy.
5. Select Enable access to restricted folders when assigning the drive letter.

Expected results:

• If the local copy mounts, investigate the Synology SMB connection, NAS file integrity, or security software scanning the network file.
• If it still fails, the Reflect mounting driver installation is the likely cause.
• If verification fails, preserve the original files and try another image in the set.

A mapped drive letter appearing in Explorer only proves that Windows assigned the letter; it does not prove that Macrium’s filesystem/mounting driver successfully attached.

3. Repair Reflect only if the driver was not blocked​

1. Check Help > About Macrium Reflect and note the exact build.
2. Use Help > Check for updates and install the newest build offered for that Free installation.
3. Restart Windows.
4. If necessary, run the original trusted Macrium installer and choose Repair, or uninstall/reinstall Reflect and restart again.

Macrium’s older troubleshooting guidance specifically recommends reinstalling Reflect when the image-mounting system driver has not loaded correctly.
A reinstall will not fix Event 3077, because Windows is deliberately blocking the driver.

4. Ways to recover the files if Event 3077 is present​

The safest choices are:

1. Install the Reflect X trial on a suitable PC and use it to open the existing .mrimg backup.
2. Use an existing Reflect rescue USB created before this problem appeared.
3. Boot the rescue environment, connect to the Synology share using the NAS credentials, and restore the required partition to a spare external disk.
4. Copy the required files from that restored disk.
5. Alternatively, use Macrium’s viBoot/VHDX method if it is available in your edition.

Do not restore the partition over your current Windows installation. Restore it only to a spare disk with no required data. Macrium officially recommends viBoot/VHDX access or restoring to spare hardware as temporary extraction methods. (kbx.macrium.com)
Temporarily uninstalling the applicable Windows security update may also restore mounting, but that reduces system security and is not a good permanent solution. I would not disable the vulnerable-driver blocklist merely to keep Reflect 8 mounting functional. Reflect 8 reached end of life on February 27, 2026. (kbx.macrium.com)
The key next result is whether Event Viewer shows 3077 mentioning psmounterex.sys, along with the laptop’s winver result and exact Reflect build.