diff --git a/bootstrap/unix-44/SYSTEM.h b/bootstrap/unix-44/SYSTEM.h
index 31fa97c5..b7d405ff 100644
--- a/bootstrap/unix-44/SYSTEM.h
+++ b/bootstrap/unix-44/SYSTEM.h
@@ -39,8 +39,8 @@ typedef unsigned short int   uint16;
 typedef signed char          int8;
 typedef unsigned char        uint8;
 
-//#define uintptr size_t
-#define uintptr int64
+#define uintptr size_t
+//#define uintptr int64
 
 // The compiler uses 'import' and 'export' which translate to 'extern' and
 // nothing respectively.
diff --git a/bootstrap/unix-48/SYSTEM.h b/bootstrap/unix-48/SYSTEM.h
index 31fa97c5..b7d405ff 100644
--- a/bootstrap/unix-48/SYSTEM.h
+++ b/bootstrap/unix-48/SYSTEM.h
@@ -39,8 +39,8 @@ typedef unsigned short int   uint16;
 typedef signed char          int8;
 typedef unsigned char        uint8;
 
-//#define uintptr size_t
-#define uintptr int64
+#define uintptr size_t
+//#define uintptr int64
 
 // The compiler uses 'import' and 'export' which translate to 'extern' and
 // nothing respectively.
diff --git a/bootstrap/unix-88/SYSTEM.h b/bootstrap/unix-88/SYSTEM.h
index 31fa97c5..b7d405ff 100644
--- a/bootstrap/unix-88/SYSTEM.h
+++ b/bootstrap/unix-88/SYSTEM.h
@@ -39,8 +39,8 @@ typedef unsigned short int   uint16;
 typedef signed char          int8;
 typedef unsigned char        uint8;
 
-//#define uintptr size_t
-#define uintptr int64
+#define uintptr size_t
+//#define uintptr int64
 
 // The compiler uses 'import' and 'export' which translate to 'extern' and
 // nothing respectively.
diff --git a/bootstrap/windows-48/SYSTEM.h b/bootstrap/windows-48/SYSTEM.h
index 31fa97c5..b7d405ff 100644
--- a/bootstrap/windows-48/SYSTEM.h
+++ b/bootstrap/windows-48/SYSTEM.h
@@ -39,8 +39,8 @@ typedef unsigned short int   uint16;
 typedef signed char          int8;
 typedef unsigned char        uint8;
 
-//#define uintptr size_t
-#define uintptr int64
+#define uintptr size_t
+//#define uintptr int64
 
 // The compiler uses 'import' and 'export' which translate to 'extern' and
 // nothing respectively.
diff --git a/bootstrap/windows-88/SYSTEM.h b/bootstrap/windows-88/SYSTEM.h
index 31fa97c5..b7d405ff 100644
--- a/bootstrap/windows-88/SYSTEM.h
+++ b/bootstrap/windows-88/SYSTEM.h
@@ -39,8 +39,8 @@ typedef unsigned short int   uint16;
 typedef signed char          int8;
 typedef unsigned char        uint8;
 
-//#define uintptr size_t
-#define uintptr int64
+#define uintptr size_t
+//#define uintptr int64
 
 // The compiler uses 'import' and 'export' which translate to 'extern' and
 // nothing respectively.
diff --git a/src/system/SYSTEM.h b/src/system/SYSTEM.h
index 31fa97c5..2622657f 100644
--- a/src/system/SYSTEM.h
+++ b/src/system/SYSTEM.h
@@ -39,8 +39,7 @@ typedef unsigned short int   uint16;
 typedef signed char          int8;
 typedef unsigned char        uint8;
 
-//#define uintptr size_t
-#define uintptr int64
+#define uintptr size_t
 
 // The compiler uses 'import' and 'export' which translate to 'extern' and
 // nothing respectively.