diff --git a/eeschema/sim/spice_value.cpp b/eeschema/sim/spice_value.cpp
index 838910d0c6..ac37fe2738 100644
--- a/eeschema/sim/spice_value.cpp
+++ b/eeschema/sim/spice_value.cpp
@@ -124,6 +124,8 @@ wxString spice_prefix( SPICE_VALUE::UNIT_PREFIX aPrefix )
     case SPICE_VALUE::PFX_GIGA:  return wxT( "G" );
     case SPICE_VALUE::PFX_TERA:  return wxT( "T" );
     }
+
+    return wxEmptyString;
 }
 
 
@@ -142,6 +144,8 @@ wxString si_prefix( SPICE_VALUE::UNIT_PREFIX aPrefix )
     case SPICE_VALUE::PFX_GIGA:  return wxT( "G" );
     case SPICE_VALUE::PFX_TERA:  return wxT( "T" );
     }
+
+    return wxEmptyString;
 }