MacOS – What causes some Network Drives using SMB no longer connect to macOS Catalina

catalinamacosNetworksmb

Running the release version of macOS Catalina some SMB shares will not connect when they did on Mojave. I noticed this first after updating to the Catalina 10.15 Beta (19A487l), I am no longer able to connect to my network drive via SMB.

This is the error:

There was a problem connecting to the server "ServerName". The server may not exist or it is unavailable at this time. Check the server name or IP address, check your network connection, and then try again.

However, I am still able to connect to the network drive from a Windows 10 machine and a macOS Mojave machine.

Is anyone else having this issue? Is it an issue with Catalina or is there something else I can do to try to resolve this?

Best Answer

The solution is in Catalina release note

https://developer.apple.com/documentation/macos_release_notes/macos_catalina_10_15_beta_2_release_notes

NetBIOS is disabled in macOS 10.15 to speed up mounting, browsing, and connecting to SMB shares. Some older printers and file servers may require NetBIOS to connect. (51119111)

To enable NetBIOS, you can create or edit the /etc/nsmb.conf file. If your system doesn't already have an /etc/nsmb.conf file, use the following Terminal commands while logged in as an Administrator:

echo "[default]" | sudo tee -a /etc/nsmb.conf
echo "port445=both" | sudo tee -a /etc/nsmb.conf

To disable NetBIOS, you can safely delete the /etc/nsmb.conf file.

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