diff --git a/CMakeLists.txt b/CMakeLists.txt
index d6a2649..4cdd1fb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -34,6 +34,8 @@ IF(DEFINE_WIN)
 	add_definitions(-D__WIN__)
 ENDIF(DEFINE_WIN)
 
+add_definitions(-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64)
+
 include_directories("${CMAKE_SOURCE_DIR}/src")
 
 add_executable(fatcat "src/fatcat.cpp" ${ALL_SOURCES})
diff --git a/src/core/FatSystem.cpp b/src/core/FatSystem.cpp
index 79cda8c..1f52e82 100644
--- a/src/core/FatSystem.cpp
+++ b/src/core/FatSystem.cpp
@@ -90,7 +90,7 @@ int FatSystem::readData(unsigned long long address, char *buffer, int size)
         cerr << "! Trying to read outside the disk" << endl;
     }
 
-    lseek64(fd, globalOffset+address, SEEK_SET);
+    lseek(fd, globalOffset+address, SEEK_SET);
 
     int n;
     int pos = 0;
@@ -112,7 +112,7 @@ int FatSystem::writeData(unsigned long long address, const char *buffer, int siz
         throw string("Trying to write data while write mode is disabled");
     }
 
-    lseek64(fd, globalOffset+address, SEEK_SET);
+    lseek(fd, globalOffset+address, SEEK_SET);
 
     int n;
     int pos = 0;
diff --git a/src/core/FatSystem.h b/src/core/FatSystem.h
index cd3c914..f9f2ca3 100644
--- a/src/core/FatSystem.h
+++ b/src/core/FatSystem.h
@@ -11,11 +11,9 @@
 
 #ifdef __APPLE__
 #define O_LARGEFILE 0
-#define lseek64 lseek
 #endif
 #ifdef __WIN__
 #define O_LARGEFILE 0
-#define lseek64 lseek
 #endif
 using namespace std;
 
diff --git a/src/fatcat.cpp b/src/fatcat.cpp
index ce23ca0..b4427e4 100644
--- a/src/fatcat.cpp
+++ b/src/fatcat.cpp
@@ -1,14 +1,10 @@
 #include <stdlib.h>
-#include<string.h>
-#ifdef __APPLE__
-#include <unistd.h>
-#else
+#include <string.h>
 #ifdef __WIN__
 #include <ctype.h>
 #include "xgetopt/xgetopt.h"
 #else
-#include <argp.h>
-#endif
+#include <unistd.h>
 #endif
 
 #include <stdio.h>