I have a job to copy files from a network drive to my local Windows 2008 server box. For most files the job works fine; however, for a specific job, I constantly get failure. It seems related to the file size (20MB).
For example, I dropped the file from a mapped network drive to my local drive. As soon as release the file, I got a warning dialog:

After a while, I got the following failure error:

I also tried to use XCOPY from command line. I got the similar error ("The specified network name is no longer avaivalable"). Actually from the File explorer, I could see files on the network drive after I got the above failures. I think it may be something else related to Windows security settings. Not sure where I could configure/change those settings.
By the way, for smaller size files, I have no issue to copy files from the same network drive.