diff --git a/src/doomdef.h b/src/doomdef.h
index 81ab7bbfb5505507f3df07b6b5709b6d4f995e81..973d95eab25f844103296188a21020f2404f2270 100644
--- a/src/doomdef.h
+++ b/src/doomdef.h
@@ -703,7 +703,9 @@ extern int
 ///	    	This stops the game from storing backups of the states, sprites, and mobjinfo tables.
 ///	    	Though this info is compressed under normal circumstances, it's still a lot of extra
 ///	    	memory that never gets touched.
+#if !(defined (__EMSCRIPTEN__) && (__SIZEOF_SIZE_T__ == 4))
 #define ALLOW_RESETDATA
+#endif
 
 /// Experimental tweaks to analog mode. (Needs a lot of work before it's ready for primetime.)
 //#define REDSANALOG