diff --git a/src/catalua.cpp b/src/catalua.cpp
index d9318f9c5728..363687ab5f04 100644
--- a/src/catalua.cpp
+++ b/src/catalua.cpp
@@ -205,6 +205,10 @@ bool save_world_lua_state( const std::string &path )
         JsonOut jsout( stream );
         jsout.start_object();
         for( const mod_id &mod : mods ) {
+            if( !mod.is_valid() ) {
+                // The mod is missing from installation
+                continue;
+            }
             jsout.member( mod.str() );
             serialize_lua_table( t[mod.str()], jsout );
         }
@@ -228,6 +232,10 @@ bool load_world_lua_state( const std::string &path )
                 // Mod could have been added to existing save
                 continue;
             }
+            if( !mod.is_valid() ) {
+                // Trying to load without the mod
+                continue;
+            }
             JsonObject mod_obj = jsobj.get_object( mod.str() );
             deserialize_lua_table( t[mod.str()], mod_obj );
         }