diff --git a/mozilla/modules/libreg/src/reg.c b/mozilla/modules/libreg/src/reg.c
index c6ff1aaa0f5..2d773440b99 100644
--- a/mozilla/modules/libreg/src/reg.c
+++ b/mozilla/modules/libreg/src/reg.c
@@ -74,10 +74,14 @@
 #include "reg.h"
 #include "NSReg.h"
 
-#if defined(XP_UNIX) || defined(XP_OS2)
+#if defined(XP_UNIX)
 #ifndef MAX_PATH
 #define MAX_PATH 1024
 #endif
+#elif defined(XP_OS2)
+#ifndef MAX_PATH
+#define MAX_PATH 260
+#endif
 #elif defined(WIN32)
 #define MAX_PATH _MAX_PATH
 #elif defined(XP_MAC)