So I have an issue with OSX, where by I can't write to NTFS shares on W2K3 servers with SMB signing turned on and IPV6 disabled for the interface. To recreate the issue: Create a folder named test that contains two files one named ._test.txt and test.txt on OSX and copy to an SMB share on W2k3. This results in spurious errors about permissions and locked files. Copying a file larger than 4k results in the error: "The operation cannot be completed because you do not have sufficient privileges or some of the items." Using mount_smbfs from a shell on OSX results in the error: "Permission denied" host:~ user$ mount_smbfs //user@server/share /Volumes/test-smbmount/ Password: host:~ user$ cp test.docx /Volumes/test-smbmount/ cp: /Volumes/test-smbmount/test.docx: Permission denied Using smbclient from a shell on OSX results in SUCCESS!!! host:~ user$ smbclient \\\\server\\\share -U user Password: Domain=[DOMAIN] OS=[Windows Server 2003 3790 Service Pack 2] Server=[Windows Server 2003 5.2] smb: \> put test.docx putting file test.docx as \test.docx (784.7 kb/s) (average 784.7 kb/s) smb: \> There is an alternative solution if you do need to drag and drop in your gui world, it'll cost you $120 link: http://www.thursby.com/products/dave-eval.html I have mailed the developer as he has obviously identified the root problem of the issue and I urged him to share his patch/resolution with Apple in the interests of the user community and a darn nice thing to do.