TROUBLESHOOTING: Slow SMB connection

This article is for macOS 10.11 to 10.13.4.

If you are mounting your Volume using SMB, you may not be able to use the full speed. The reason is that by default, between macOS 10.11 and macOS 10.13, SMB signing is turned on, which slows down the communication.

Note that in macOS 10.13.4 and later, packet signing is off by default, so you should not 

When SMB signing is turned on, all SMB packets are signed, and thus it makes secure communications between two devices. This is mainly useful if you connect through an unsecured network. If your network is secure, and you want to enjoy all the speed of SMB, follow the instructions in the following article to disable SMB signing:

https://support.apple.com/en-us/HT205926

Note that disabling SMB signing will also speed up 1Gb networks, but it is much clearer with 10Gb connections.