diff --git a/hecl/driver/CMakeLists.txt b/hecl/driver/CMakeLists.txt
index 2280145d7..d69e7fa53 100644
--- a/hecl/driver/CMakeLists.txt
+++ b/hecl/driver/CMakeLists.txt
@@ -28,6 +28,7 @@ target_link_libraries(hecl
     ${ZLIB_LIBRARIES} ${LZO_LIB} ${PLAT_LIBS} ${BOO_SYS_LIBS})
 
 if(COMMAND cotire)
+  set_target_properties(hecl PROPERTIES COTIRE_ADD_UNITY_BUILD FALSE)
   cotire(hecl)
 endif()
 endif()
diff --git a/hecl/lib/CMakeLists.txt b/hecl/lib/CMakeLists.txt
index 111a6d71b..b50fa5a35 100644
--- a/hecl/lib/CMakeLists.txt
+++ b/hecl/lib/CMakeLists.txt
@@ -70,6 +70,7 @@ if(COMMAND add_sanitizers)
   add_sanitizers(hecl-common)
 endif()
 if(COMMAND cotire)
+  set_target_properties(hecl-common PROPERTIES COTIRE_ADD_UNITY_BUILD FALSE)
   cotire(hecl-common)
 endif()