diff --git a/src/V3Global.h b/src/V3Global.h
index 2716dd75e..546f7e2e6 100644
--- a/src/V3Global.h
+++ b/src/V3Global.h
@@ -23,7 +23,7 @@
 
 #include "config_build.h"
 #ifndef HAVE_CONFIG_BUILD
-# error "Something failed during ./configure as config_build.h is incomplete."
+# error "Something failed during ./configure as config_build.h is incomplete. Perhaps you used autoreconf, don't."
 #endif
 
 #include "verilatedos.h"
diff --git a/src/VlcMain.cpp b/src/VlcMain.cpp
index a00fd72ee..c4e27b821 100644
--- a/src/VlcMain.cpp
+++ b/src/VlcMain.cpp
@@ -21,7 +21,7 @@
 // Cheat for speed and compile .cpp files into one object
 #include "config_build.h"
 #ifndef HAVE_CONFIG_BUILD
-# error "Something failed during ./configure as config_build.h is incomplete."
+# error "Something failed during ./configure as config_build.h is incomplete. Perhaps you used autoreconf, don't."
 #endif
 
 #include "verilatedos.h"