If this is a private key which you're using in the real network, change it now.
The key I pasted is a private key from the testnet so it's all safe (thank you anyway).
I was trying to import a testnet account from the GUI into the CLI.
I copied the private key from the GUI and wanted to use it in the
import_key command in the CLI but it failed.
You need to modify libraries/chain/include/graphene/chain/config.hpp to set the prefix and/or other values to "TEST".
And maybe need to modify libraries/chain/protocol/types.cpp
Would it mean I need to recompile the CLI to be able to access the testnet?
I hope there is a more practical solution - I'm sure xeroc will shed some light on this.