diff --git a/indra/llvfs/lldir_mac.cpp b/indra/llvfs/lldir_mac.cpp
index 114dc0c47..b6ba5e308 100644
--- a/indra/llvfs/lldir_mac.cpp
+++ b/indra/llvfs/lldir_mac.cpp
@@ -150,7 +150,7 @@ LLDir_Mac::LLDir_Mac()
 		CFURLRef resourcesURLRef = CFBundleCopyResourcesDirectoryURL(mainBundleRef);
 		CFURLRefToLLString(resourcesURLRef, mAppRODataDir, true);
 		
-		U32 build_dir_pos = mExecutableDir.rfind("/indra/build-darwin-");
+		size_t build_dir_pos = mExecutableDir.rfind("/indra/build-darwin-");
 		if (build_dir_pos != std::string::npos)
 		{
 			// ...we're in a dev checkout