diff --git a/src/validation.cpp b/src/validation.cpp
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1348,8 +1348,8 @@
 }
 
 /** Abort with a message */
-bool AbortNode(const std::string &strMessage,
-               const std::string &userMessage = "") {
+static bool AbortNode(const std::string &strMessage,
+                      const std::string &userMessage = "") {
     SetMiscWarning(strMessage);
     LogPrintf("*** %s\n", strMessage);
     uiInterface.ThreadSafeMessageBox(
@@ -1361,8 +1361,8 @@
     return false;
 }
 
-bool AbortNode(CValidationState &state, const std::string &strMessage,
-               const std::string &userMessage = "") {
+static bool AbortNode(CValidationState &state, const std::string &strMessage,
+                      const std::string &userMessage = "") {
     AbortNode(strMessage, userMessage);
     return state.Error(strMessage);
 }