diff --git a/Cantera/src/thermo/Makefile.in b/Cantera/src/thermo/Makefile.in
index 76806a1a6..30791cf4c 100644
--- a/Cantera/src/thermo/Makefile.in
+++ b/Cantera/src/thermo/Makefile.in
@@ -54,14 +54,14 @@ THERMO_H   = State.h Elements.h Constituents.h Phase.h mix_defs.h \
 ifeq ($(do_electro),1)
 do_issp = 1
 ELECTRO_OBJ = MolalityVPSSTP.o  VPStandardStateTP.o \
-              IdealSolidSolnPhase.o IdealMolalSoln.o \
+              IdealMolalSoln.o \
               WaterPropsIAPWSphi.o WaterPropsIAPWS.o WaterProps.o \
               PDSS.o WaterPDSS.o \
 	      HMWSoln.o HMWSoln_input.o DebyeHuckel.o \
               IdealGasPDSS.o WaterSSTP.o
 
 ELECTRO_H = MolalityVPSSTP.h  VPStandardStateTP.h \
-               IdealSolidSolnPhase.h IdealMolalSoln.h \
+               IdealMolalSoln.h \
                WaterPropsIAPWSphi.h WaterPropsIAPWS.h WaterProps.h \
                PDSS.h WaterPDSS.h HMWSoln.h electrolytes.h \
 	       DebyeHuckel.h IdealGasPDSS.h WaterSSTP.h
diff --git a/Cantera/src/thermo/ThermoFactory.cpp b/Cantera/src/thermo/ThermoFactory.cpp
index c125936ef..1dedde1f6 100644
--- a/Cantera/src/thermo/ThermoFactory.cpp
+++ b/Cantera/src/thermo/ThermoFactory.cpp
@@ -24,7 +24,10 @@
 #include "speciesThermoTypes.h"
 #include "SpeciesThermoFactory.h"
 #include "IdealGasPhase.h"
+
+#ifdef WITH_IDEAL_SOLUTIONS
 #include "IdealSolidSolnPhase.h"
+#endif
 
 #ifdef WITH_PURE_FLUIDS
 #include "PureFluidPhase.h"
@@ -118,9 +121,11 @@ namespace Cantera {
             th = new EdgePhase;
             break;
 
+#ifdef WITH_IDEAL_SOLUTIONS
         case cIdealSolidSolnPhase:
             th = new IdealSolidSolnPhase();
             break;
+#endif
 
 #ifdef WITH_METAL
         case cMetal: