bug in AzCopy utility? "The specified network name is no longer available"

I am trying to copy 400gb of media files for deployment deadline in a few days and need to get the files copied from an old virtual machine to Azure file storage. I was using multithreaded robocopy but AzCopy seems to be the fastest option out there. When I gave AzCopy the entire 400gb root folder to process, it choked, but it worked fine on one subfolder at a time. Here's the powershell script I wrote to iterate over all of the folders that robocopy hadn't gotten to yet:

ls -dir \\acsrv\d$\Inetpub\wwwroot\mysite\ClientFiles\[D-Z]* | ForEach-Object { .\AzCopy "/Source:$($_.FullName)" "/Dest:https://mynewsiteinazure.file.core.windows.net/files/ClientFiles/$($_.BaseName)" /DestKey:bowloblaw /XO /V }

I was letting it run over night, but then it died on me during one of its copy operations, which hung up the entire script. See error message below. I am connected to the networks' VPN so I can access the source machine, but it seems like it loses that connection once in a while.

So I guess my question is: Is this a bug in AzCopy or am I doing something wrong? I have added silently continue flags I saw on here. I will try to log this as an error on their github page. Thanks!

Unhandled Exception: System.Runtime.InteropServices.COMException: The specified network name is no longer available. (Ex ception from HRESULT: 0x80070040) at Microsoft.WindowsAzure.Storage.AzCopy.LongPathHelpers.NativeMethods.ThrowExceptionForLastWin32ErrorIfExists(Int32[ ] expectErrorCodes) at Microsoft.WindowsAzure.Storage.AzCopy.LongPathHelpers.LongPathFile.GetLastWriteTimeUtc(String path) at Microsoft.WindowsAzure.Storage.AzCopy.LocationHelper.GetLastModifiedTime(Object transferObject, Boolean fetch) at Microsoft.WindowsAzure.Storage.AzCopy.AzCopy.ShouldTransferCallback(Object source, Object dest) at Microsoft.WindowsAzure.Storage.DataMovement.MultipleObjectsTransfer.<>c__DisplayClass35_0.b__0()

at System.Threading.Tasks.Task`1.InnerInvoke() at System.Threading.Tasks.Task.Execute() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Microsoft.WindowsAzure.Storage.DataMovement.MultipleObjectsTransfer.d__36.MoveNext() at Microsoft.WindowsAzure.Storage.DataMovement.MultipleObjectsTransfer.EnumerateAndTransfer(TransferScheduler schedul er, CancellationToken cancellationToken) at System.Threading.Tasks.Task.Execute() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.WindowsAzure.Storage.DataMovement.MultipleObjectsTransfer.d__30.MoveNext() --- End of stack trace from previous location where exception was thrown --- at Microsoft.WindowsAzure.Storage.DataMovement.MultipleObjectsTransfer.d__30.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.WindowsAzure.Storage.DataMovement.DirectoryTransfer.d__17.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.WindowsAzure.Storage.DataMovement.TransferManager.d__73.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.WindowsAzure.Storage.DataMovement.TransferManager.d__70.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at Microsoft.WindowsAzure.Storage.AzCopy.BlobFileTransfer.DoTransfer()
at Microsoft.WindowsAzure.Storage.AzCopy.AzCopy.ExecuteTransfer()
at Microsoft.WindowsAzure.Storage.AzCopy.AzCopy.Execute(String[] args) at Microsoft.WindowsAzure.Storage.AzCopy.AzCopy.Main(String[] args)