I am very new so thanks for the help, On MacOs I'm trying to attache two nodes to a private network, one node is succesfully launched to an existing bootnode. Everything I've read says to launch the second in a new terminal windo but it returns "fatal error lanching protocol stack: datadir already used by another process."

Am I missing a permission that allows me to run geth in multiple terminal windows on MacOs?

I think this

1 Answer 1


Are you using Geth? Seems like you are using the same datadir for both instances.

geth --port 30303 --datadir ~/.ethA
geth --port 30304 --datadir ~/.ethB

You can check out the command option here.

  • It's should be the same --datadir unless I'm missing something. I follow the directions I've been given to start separate folders for each node. Mar 22, 2023 at 21:36
  • datadir is the database entry for your nodes so it is not really related to the folder directory. I am not 100% sure if there is a way to allow two nodes to share the same directory. But this should be a quick fix for this error message. Mar 23, 2023 at 3:34

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