Hi,

I built a second Unraid server (TowerW), which I store at my parents as an offsite backup. It was assembled last summer, and I use Syncback Free to synchronize my home Unraid server (TowerV) to a 16 TB My Cloud EX2 which I transfer back and forth when I go visit them. I use a Windows VM on each UnRaid server to run Syncback Free. Syncback has been doing a great job sync'ing my files, so I back-up the documents on the unraid server at my parents (TowerW), and they backup my home server (TowerV).

On my last two visits, the server at my parents has been failing the sync'ing. The message in the Windows VM running on the UnRaid server, to which I connect, with RDP, is that the network connection to the drive it's trying to sync has failed. I brought the server home with me, the last time, and have tried to run Syncback on my home Unraid Server Windows VM, and I'm still getting the message that the network connection to the array has failed. What I don't understand is how can the network connection to the array fail, when it's obviously still working because I can be signed onto the Unraid GUI over my network, or the Windows VM running on that server, which runs extremely stable and doesn't disconnect.

I tried to simply copy a directory over the network, not using Syncback, but it failed quickly.  The very first file I tried to copy came up with Error 0x8007003B: An unexpected network error occurred. I think Syncback is related to my issues.

I ran the diagnostics, and have attached them for the Gurus here to review.

Thank you is advance,

Greg

towerw-diagnostics-20191209-2203.zip

8 hours ago, Greg F said:

Error 0x8007003B: An unexpected network error occurred.

This is a general Windows error message for a lot of SMB problems-- it does not pinpoint any specific problem, only that you have one.  You are using WIN10 and MS has made more changes to SMB on WIN10 in the past year than I can count.  You are not the only one to have encountered issues.  Start by going through this sticky thread:

 

   https://forums.unraid.net/topic/53172-windows-issues-with-unraid/

 

You might want to start at (or near) the end as that is where the most recent solutions are found. 

8 hours ago, Greg F said:

I tried to simply copy a directory over the network, not using Syncback, but it failed quickly. 

Where you using Windows Explorer when this happened?  Was it a mapped drive?  Or did you simply use Windows Explorer to move from   Network   >> server   >> share  >> file   ? 

A non-obvious cause of such an issue that can occur is a problem with the network on the windows system.   I had the case where everything seemed to work fine until I tried to copy large files and they would error out with the described symptoms.   The fix in my case was to switch to a different network card and since doing so the symptoms have not reappeared.

It would appear the issue is definitely Microsoft changing SMB on Windows 10. My previous attempt to manually copy files was between two mapped drives in a Windows VM, by using Windows Explorer. This time, I mapped the two drives in Nemo on Linux Mint Debian edition, and successfully copied 84GB between two folders.

 

I'll read the sticky thread for some helpful hints in resolving the issues.

 

Thank you for your expert help, I never would have thought of the SMB issue.