diff --git a/src/openrct2/rct2/S6Exporter.cpp b/src/openrct2/rct2/S6Exporter.cpp
index 91b8f6dbcb..aaee9c9b44 100644
--- a/src/openrct2/rct2/S6Exporter.cpp
+++ b/src/openrct2/rct2/S6Exporter.cpp
@@ -166,7 +166,8 @@ void S6Exporter::Export()
     {
         const rct_object_entry * entry     = get_loaded_object_entry(i);
         void *                   entryData = get_loaded_object_chunk(i);
-        if (entryData == (void *)-1)
+        // RCT2 uses (void *)-1 to mark NULL. Make sure it's written in a vanilla-compatible way.
+        if (entryData == nullptr || entryData == (void *)-1)
         {
             Memory::Set(&_s6.objects[i], 0xFF, sizeof(rct_object_entry));
         }