Mikrotik SMB Share - Veeam Backup Error

RouterOS General
1

Hi,

has anyone else tried useing SMB Share on Mikrotik with Veeam Backup Agent 6.x (currently using latest 6.3).
I tried it on Mikrotik hAP-AX3 and ROS 7.15.x til ROS 7.16.1.
Share is on USB (Nvme disk). I tried also other disks and different filesystem in ROS..
I always get this error in Veeam Backup Agent:

10.1.2025 20:57:13 :: Error: An unexpected network error occurred. Failed to flush file buffers. File: [\\192.168.0.1\Backup\Backup\Backup2025-01-10T205627.vbk]. Failed to flush storage file [\\192.168.0.1\Backup\Backup\Backup2025-01-10T205627.vbk] Failed to backup text locally. Backup: [VBK: 'veeamfs:0:6745a759-2205-4cd2-b172-8ec8f7e60ef8 (bba13387-1333-41af-98e3-e72a5a7a6c90)\summary.xml@\\192.168.0.1\Backup\Backup\Backup2025-01-10T205627.vbk']. Agent failed to process method {DataTransfer.BackupText}

I have opened the SUP but they did not find anything. So I am asking here if anybody else has tried it or maybe can test it..

2

Found some information on the Veeam-Forum, that depending on the Configuration
it tries to write a File on the SMB-Share… Wasn`t able to check it myself.

Does the credential you use to access the Files on the Microtik device habe write Privilege?

3

Isnt’ it easier to use any NAS instead of router?

4

Hi,

sorry for late response.
So the credentials work (Read/write). I am able to write normal files from Windows Explorer with same credentials to this share.

As for NAS usage. Of course it works and is a better option but my goal here is to use a single device (router with SMB functionality).

BTW. The problem still exists in version 7.17 (hAP-AX3).

I do not know if it is a limitation of Veeam backup agent (Which works ok on QNAP share, local USB disk etc..) or something in SMB implementation on ROS.

If anyone else can recreate this behavior it would mean it is not just me :slight_smile:

Simple steps:

  1. Download Veeam Backup Agent Free
  2. Entire Computer Backup
  3. Target SMB Share on Mikrotik Router
5

Hello,
I also got same issue Failed to flush file buffers. - also hap ax3.
Did you manage to solve the problem?

6

No sadly issue still exists in ROS 7.19.4 (hAP-AX4). USB Nvme Disk formated in ext4.
SMB Share and lateset version of Veeam Agent 6.3.2. ..

I am really interested if anybody else had the same problem or just me and Jt522

7

Hi Yes, I have exactly the same configuration, and exactly the same problem.

C53UiG+5HPaxD2HPaxD (hAP ax3) ROS 7.19.6
Windows 11 Pro 24H2
Veeam Agent for Microsoft Windows 6.3.2.1302

Error message:

Usually this:
22.10.2025 16:55:40 :: Error: An unexpected network error occurred. Failed to flush file buffers. File: [\192.168.144.1\backup\Job PNX-lap\Job PNX-lap2025-10-22T165456.vbk]. Failed to flush storage file [\192.168.144.1\backup\Job PNX-lap\Job PNX-lap2025-10-22T165456.vbk] Failed to backup text locally. Backup: [VBK: 'veeamfs:0:6745a759-2205-4cd2-b172-8ec8f7e60ef8 (6e3de9d7-c34c-0648-a191-fb112f1d5430)\summary.xml@\192.168.144.1\backup\Job PNX-lap\Job PNX-lap2025-10-22T165456.vbk']. Agent failed to process method {DataTransfer.BackupText}

And once there was this error:
22.10.2025 17:06:09 :: Error: Shared memory connection was closed. Failed to upload disk. Skipped arguments: [EmulatedDiskSpec>]; Agent failed to process method {DataTransfer.SyncDisk}. Exception from server: An unexpected network error occurred. Failed to write data to the file [\192.168.144.1\backup\Job PNX-lap_1\Job PNX-lap2025-10-22T170507.vbk]. Failed to download disk '2e253b8a-1445-4938-b38b-ca7c7c1974ee'

8

Try Opening the ticket on support@mikrotik.com.. Maybe they will acknowladge it if there a more tickets like this.. My ticket was closed and I am pretty sure they did not test it since others have the same problem!

It has been more than 10 months from initial report here and SUP…

Quite sad about that..