diff --git a/src/sat/cnf/cnfUtil.c b/src/sat/cnf/cnfUtil.c
index ac6d0ebf1..7886b8a3b 100644
--- a/src/sat/cnf/cnfUtil.c
+++ b/src/sat/cnf/cnfUtil.c
@@ -23,13 +23,18 @@
 
 ABC_NAMESPACE_IMPL_START
 
+#ifdef _MSC_VER
+#define unlink _unlink
+#else
+#include <unistd.h>
+#endif
+
 #ifdef ABC_USE_PTHREADS
 
 #ifdef _WIN32
 #include "../lib/pthread.h"
 #else
 #include <pthread.h>
-#include <unistd.h>
 #endif
 
 #endif