Mac: 10.6: Fix Samba write access from OS X to Linux servers

After installing the OS X Snow Leopard 10.6.3 update, I found that I could no longer write to Samba (SMB) volumes shared from my Linux server (running Ubuntu 9.10 Karmic Koala) that I had mounted on OS X.

Whenever I tried to copy a file from OS X to the mounted Samba drive, I got this error message:

The operation can’t be completed because you don’t have permission to access some of the items.

To solve the problem, turn off Unix extensions in your Samba server (Ubuntu 9.10 in my case) by adding the following line to smb.conf in the global settings block, and then restarting Samba:

unix extensions = no

You might also need to unmount and re-mount your Samba volumes from OS X after you make this change