Stop bitcoind before running a new instance
MODIFY
WalletWasabi.Tests/NodeBuilding/CoreNode.cs
WalletWasabi.Tests/NodeBuilding/CoreNode.cs
@@ -92,7 +92,8 @@ namespace WalletWasabi.Tests.NodeBuilding
{"regtest.whitebind", "127.0.0.1:" + _ports[0].ToString()},
{"regtest.rpcport", _ports[1].ToString()},
{"regtest.printtoconsole", "0"}, // Set it to one if don't mind loud debug logs
- {"regtest.keypool", "10"}
+ {"regtest.keypool", "10"},
+ {"regtest.pid", "bitcoind.pid"}
};
config.Import(ConfigParameters);
File.WriteAllText(Config, config.ToString());

Stop bitcoind before running a new instance