I would recommend trying my exact file, at least as an experiment. If it doesn’t work for you, you can either delete it or edit it yourself. Just remember that after you change it, you should restart your machine.
Here’s a single-line command that will copy my nsmb.conf file to the correct location on your machine. It requires your password to do this, because writing to that location on your machine is privileged. It doesn’t run any code or do anything nefarious. If you’re nervous about it, others can chime in to ease your concerns.
Go into your Applications folder in Finder, then inside of the Utilities folder, choose Terminal to get to a command prompt (where you can type in commands). Once you’re at the command prompt, copy and paste this command, then press enter to execute it:
sudo curl -o /etc/nsmb.conf https://gist.githubusercontent.com/mikeswanson/309db72a5918c76e4d11e8e049ebf0c8/raw/e4993d623de2bea384b8a0a23a65ffad9d9e8b63/nsmb.conf
As I mentioned, you’ll be asked for your password to continue. Nothing will confirm that it worked, so you might then want to type this command followed by enter:
cat /etc/nsmb.conf
This will show you the contents of the file you just copied. If the file copy didn’t work for some reason, this command will complain that there is no such file.
If everything looks good, you can type:
exit
Followed by enter to get out of the Terminal app. Then, you can restart your machine and test.
If you later find that it didn’t help, you can either edit that file based on other suggestions, or you can safely remove it by going back to the Terminal app and typing:
sudo rm /etc/nsmb.conf
Followed by enter. Because this also requires privileges, you’ll be asked for your password to confirm it. Then, you can type “exit” to get out of the Terminal (as before) and reboot your machine for the changes to take effect.
