Snow Leopard Error -50 when copying to an SMB share

Symptom

Snow Leopard client copying file to SMB will get a –50 unkown error and the copying will halt. This only happens to Snow Leopard and only to SMB. Copying the same files to AFP works fine. It is also only on certain files. We can take this file to another Snow Leopard machine and reproduce it every time.

Cause

We found out that it has to do with files with resource fork. I think Snow Leopard and Leopard no longer embed resource fork into files anymore. But I am guessing these files were touched or created by older Apple OS. This explains why out of thousands of files, we only see some files with this problem. This is due to the fact that the Snow Leopard Client now defaults to using NTFS Streams rather than AppleDouble files (dot underscore files) to store the resource fork.

Solution

Turn off NTFS Streams support in Snow Leopard. You can do this on the client by running this command.

echo "[default]" | sudo tee -a /etc/nsmb.conf

echo "streams=no" | sudo tee -a /etc/nsmb.conf

Of course this would be a pain if you have to touch every clients. An easier way is to touch the share by creating a file at the root of the share called ".com.apple.smb.streams.off". As this is a hidden file, it is probably best to do this from the command line.

cd /Volumes/sharename/

touch .com.apple.smb.streams.off

No reboot is needed. Client just need to dismount and mount the share again.