I have a scheduled, nightly, full File & Folder backup of an internal data disk.  Nothing else is stored on this disk except data.  The destination is an external USB HD.  Twice in the last few weeks the backup has failed automatic verification.  The earlier backup failed with an error code 23.  Last night's backup failed with error code 121.  After the 1st failure, I ran a variety of Disk tools to check the health of the disk.  All tests passed (chkdsk, Western Digital disk diagnostics, and Hard Disk Sentinel surface test).  I have included the log from last night's failed verification.

EDIT:  This external drive also stores a variety of disk images that are created nightly.  None of them fail verification; only this F&F backup.

Backup ID - EA3453BF5148A6FA

--------------------------------------------------------------------------------
Backup Summary


--------------------------------------------------------------------------------
Backup Definition File: C:\Users\David\Documents\Reflect\7 Western Digital F&F (Disk 1-W) Daily.xml
Auto Verify: Y
Maximum File Size: Automatic
Compression: Medium
Password: N
NTFS Permissions: Y
Folder Reparse Points: Follow user reparse points, Do not follow system reparse points
Backup set matching: Similar - Match on backups with at least one matching folder
Shutdown: Forced
Email On Success: Y
Recipients: xxxx
Email On Warning: Y
Recipients: xxxx
Email On Failure: Y
Recipients: xxxx
Current Time: 9/14/2023 4:31:24 AM


--------------------------------------------------------------------------------
Destination
Backup Type: Full
File Name: W:\Reflect F&F (D) Daily\EA3453BF5148A6FA-00-00.mrbak


--------------------------------------------------------------------------------
Backup Sources
Folder: D:\Documents\
Include File Filter: *.*
Exclude File Filter: *.temp; *.tmp; *.bak; *.~*
Include Sub Folders: Y
Exclude Folder Filter:
Exclude Hidden Files: N
Exclude System Files: N


--------------------------------------------------------------------------------
Creating Volume Snapshot - Please Wait
Volume Snapshots Created
D:\ \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy3
Starting Backup - Thursday, September 14, 2023 4:31 AM
Write Method: Using Direct Disk I/O
Destination Drive: My Book (W - Free Space 1.11 TB
Image Guardian: Protected
Free space threshold: Delete oldest backup sets when free space is less than 5.00 GB

Determining files to copy
Total Number of Files: 38715
Total Number of Folders: 3561
Total Size: 80.64 GB
Copying files
Saving cluster information
Saving Index
New File: 78.93 GB EA3453BF5148A6FA-00-00.mrbak
Verifying 'EA3453BF5148A6FA-00-00.mrbak'
Failed
Gathering Windows Events - Please Wait


--------------------------------------------------------------------------------
Email Notifications
Recipients: xxxx
Email notification sent


--------------------------------------------------------------------------------
Backup aborted! - 'EA3453BF5148A6FA-00-00.mrbak' Verification failed at 16% (Error reading 262153 bytes from file. Error code = 121)


--------------------------------------------------------------------------------

Macrium Reflect Home v8.1.7638 - 76-xxxx

Examining the Backup Log Summary, I noticed that both failed backups show "Error reading 262153 bytes from file" in the summaries.  Not sure what that means but thought I'd throw it out there.



I might add that I also do a nightly image (mrimg.) of the same disk with automatic verification and I have never seen a failure of the image.  Only with a backup (mrbak).

The error code 121 may be referencing the semaphore timeout period has expired, this means that the backup target file system has stopped communicating with Windows and caused all open file handles to drop. This doesn't necessarily mean the issue lies on the disk but possibly the USB wire or the port itself. It could also be a one-off error that Windows likes to throw every now and then. 

If you are using an external drive as the destination disk can you please try and connect this directly to the motherboard via the USB ports and see if this changes anything? 

Kind Regards

Joe A

Macrium Support Team

See our reviews on

Thanks for replying @JoeA!

Last night's verification was successful.

The external USB storage device is connected directly to a USB port on the computer.  I'll replace the cable and keep an eye on it for awhile.  If another failure happens, I'll connect the new cable to a different port.

In any event, I'll keep you in the loop.

@JoeA  I replaced the USB cable today so we'll see how the F&F backups go this week.

Last night's scheduled F&F backup failed verification (log attached).  I will attach the new USB cable to a different 3.0 port and see if that makes a difference.  I find it odd that nightly images (mrimg) are not failing.  It's only File & Folder backups that are failing verification.

Backup Summary


--------------------------------------------------------------------------------
Backup Definition File: C:\Users\David\Documents\Reflect\7 Western Digital F&F (Disk 1-W) Daily.xml
Auto Verify: Y
Maximum File Size: Automatic
Compression: Medium
Password: N
NTFS Permissions: Y
Folder Reparse Points: Follow user reparse points, Do not follow system reparse points
Backup set matching: Similar - Match on backups with at least one matching folder
Shutdown: Forced
Email On Success: Y
Recipients: XXXX
Email On Warning: Y
Recipients: XXXX
Email On Failure: Y
Recipients: XXXX
Current Time: 9/18/2023 4:31:12 AM


--------------------------------------------------------------------------------
Destination
Backup Type: Full
File Name: W:\Reflect F&F (D) Daily\BD19A1149B76C85D-00-00.mrbak


--------------------------------------------------------------------------------
Backup Sources
Folder: D:\Documents\
Include File Filter: *.*
Exclude File Filter: *.temp; *.tmp; *.bak; *.~*
Include Sub Folders: Y
Exclude Folder Filter:
Exclude Hidden Files: N
Exclude System Files: N


--------------------------------------------------------------------------------
Creating Volume Snapshot - Please Wait
Volume Snapshots Created
D:\ \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy12
Starting Backup - Monday, September 18, 2023 4:31 AM
Write Method: Using Direct Disk I/O
Destination Drive: My Book (W - Free Space 996.04 GB
Image Guardian: Protected
Free space threshold: Delete oldest backup sets when free space is less than 5.00 GB

Determining files to copy
Total Number of Files: 38715
Total Number of Folders: 3561
Total Size: 80.66 GB
Copying files
Saving cluster information
Saving Index
New File: 78.95 GB BD19A1149B76C85D-00-00.mrbak
Verifying 'BD19A1149B76C85D-00-00.mrbak'
Failed
Gathering Windows Events - Please Wait


--------------------------------------------------------------------------------
Email Notifications
Recipients: XXXX
Email notification sent


--------------------------------------------------------------------------------
Backup aborted! - 'BD19A1149B76C85D-00-00.mrbak' Verification failed at 64% (Error reading 262153 bytes from file. Error code = 23)


--------------------------------------------------------------------------------

Macrium Reflect Home v8.1.7638 - 76-XXXX

Hi @capair45, 

Can you please open a support ticket so we can collect a support submission from you?

Kind Regards

Joe A

Macrium Support Team

See our reviews on

#248062 Submitted

MR Support staff is researching this.  In the meantime, can anyone help me understand the significance of, "Error reading 262153 bytes from file"?  This is shown in all 3 of the failures I've seen so far.

Additionally, a manual F&F backup with verification just completed successfully.

I do notice that on both failures, you're getting different error codes.  The first log's error code was 121 and the 2nd's is 23.