SQL Server – Backup – Error – The specified network name is no longer available.)’ while attempting ‘FlushFileBuffers’


Attempting SQL Server backup to our Network File Server, but failing with an error message stating “The operating system returned the error ’64(The specified network name is no longer available.)’ while attempting ‘FlushFileBuffers’“.

Error Message

The operating system returned the error '64(The specified network name is no longer available.)' while attempting 'FlushFileBuffers' on '\\labfileserver\sqlbackup\hrdb_backup_2015_08_18_161953_6973966.bak'.  BACKUP DATABASE is terminating abnormally.



The resolution is well covered on the Internet:

  2. Drivers

Increase Session Timeout

Visually we can easily change the registry using regedit, but let us use command line.


REG QUERY HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters /s




  1. We can see that SessTimeout is not listed
  2. And, as such we are using the default timeout of 45 seconds ( https://technet.microsoft.com/en-us/library/cc938292.aspx )


REG ADD HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters /v SessTimeout /t REG_DWORD /d 360 




  • Thanks goodness, we were successful


REG QUERY HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters /v SessTimeout




  • We got back 0x168
  • 0x signifies Hex, and so let us covert to Decimal.  0x168 is 360 decimal

Retry Backup

The next time we retried backup, we were successful.

I think the problem is due to the way SQL Server backups database.  It allocates a big chunk of sparse file to make sure that the needed storage is available and reserved.  It does a lot of work and then goes back and writes out the backup file in chunks.

My thinking is that this causes network timeouts.

Using Compression

Let us make sure that we are using SQL Server Backup Compression:


We checked the “Compress backup” setting.

And, that saved us some storage the next time we attempted a backup.


The initial backup was 263 MB and the new one is 185 MB.

We thus saved 30%.

Other Errors

The good thing about writing is that it forces one into a hole.  By it’s very nature, you almost have to check out more things out.  In our case, there are numerous errors being logged in the Event Viewer.

Event Viewer – System

  • Type => Warning
  • Source => MrxSmb
  • Event => 3019


Quick Explanation:

  1. Every minute, a few entries are being logged

It appears that the registry entry item that we just changed will be effectual in better understanding this error, as well.

This is based on a quick reading of:

MSDN Blogs > Microsoft Open Specifications Support Team Blog > CIFS and SMB Timeouts in Windows


Again, thanks goodness for the Internet.

I really thought it was just out of date drivers (disk and network) and was spending time seeking the latest files out over the Internet.

But, since the registry patch worked without us having to restart the MS SQL Server Instance nor the host, life is good!


Registry / Command Line

  1. Reg /query
  2. Reg /add

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