diff --git a/indra/llmath/llvolumemgr.cpp b/indra/llmath/llvolumemgr.cpp
index 07df1ccaa..a8c2766cb 100644
--- a/indra/llmath/llvolumemgr.cpp
+++ b/indra/llmath/llvolumemgr.cpp
@@ -27,6 +27,7 @@
 
 #include "llvolumemgr.h"
 #include "llvolume.h"
+#include "llthread.h"
 
 
 const F32 BASE_THRESHOLD = 0.03f;
diff --git a/indra/llmath/llvolumemgr.h b/indra/llmath/llvolumemgr.h
index c242ca68c..c2953655a 100644
--- a/indra/llmath/llvolumemgr.h
+++ b/indra/llmath/llvolumemgr.h
@@ -31,7 +31,6 @@
 
 #include "llvolume.h"
 #include "llpointer.h"
-#include "llthread.h"
 
 class LLVolumeParams;
 class LLVolumeLODGroup;