Comment 10 for bug 211632

It might also be worthy to note that this issue can be caused with the way VLC handles the SMB access. If you are trying to connect to an SMB share through VLC it will apparently use its own "SMB Access Module" which looks to default to using the current username and no password. This can be changed in the VLC settings to use a different username/pass/workgroup.

This can cause a problem if you're accessing a windows share that requires a password, or if the username you're using requires a password on the windows share. For me, I have the user "jrennell" on the windows machine where my media is and I log into Ubuntu with "jrennell". Since "jrennell" is a user on the windows machine, trying to log in as "jrennell" with a blank password was not allowed. Changing the access module to "anonymous" allowed me to open files from nautilus without a problem.

I had the exact problem described in this bug report, and could open then from the "file > open file" method through VLC.