diff --git a/crlcore/src/cyclop/CyclopMain.cpp b/crlcore/src/cyclop/CyclopMain.cpp
index ebe4214d..0999f220 100644
--- a/crlcore/src/cyclop/CyclopMain.cpp
+++ b/crlcore/src/cyclop/CyclopMain.cpp
@@ -25,7 +25,7 @@ namespace boptions = boost::program_options;
 #include  <QtGui>
 #if (QT_VERSION >= QT_VERSION_CHECK(4,5,0)) and \
     (QT_VERSION <  QT_VERSION_CHECK(5,0,0)) and \
-    not defined (__APPLE__)
+    not defined (__APPLE__) and not defined (__CYGWIN__)
 #  include  <QGtkStyle>
 #endif
 
@@ -199,7 +199,7 @@ int main ( int argc, char *argv[] )
       auto_ptr<QApplication> qa ( new HApplication(argc,argv) );
 #if (QT_VERSION >= QT_VERSION_CHECK(4,5,0)) and \
     (QT_VERSION <  QT_VERSION_CHECK(5,0,0)) and \
-    not defined (__APPLE__)
+    not defined (__APPLE__) and not defined (__CYGWIN__)
       qa->setStyle ( new QGtkStyle() );
 #endif
       Graphics::enable ();
diff --git a/hurricane/src/viewer/PyHApplication.cpp b/hurricane/src/viewer/PyHApplication.cpp
index 737bfeb9..f6f10438 100644
--- a/hurricane/src/viewer/PyHApplication.cpp
+++ b/hurricane/src/viewer/PyHApplication.cpp
@@ -19,7 +19,7 @@
 #include <QtGui>
 #if (QT_VERSION >= QT_VERSION_CHECK(4,5,0)) and \
     (QT_VERSION <  QT_VERSION_CHECK(5,0,0)) and \
-    not defined (__APPLE__)
+    not defined (__APPLE__) and not defined(__CYGWIN__)
 #  include  <QGtkStyle>
 #endif
 
@@ -100,7 +100,7 @@ extern "C" {
     ha = new HApplication(argc,argv);
 #if (QT_VERSION >= QT_VERSION_CHECK(4,5,0)) and \
     (QT_VERSION <  QT_VERSION_CHECK(5,0,0)) and \
-    not defined (__APPLE__)
+    not defined (__APPLE__) and not defined (__CYGWIN__)
     ha->setStyle ( new QGtkStyle() );
 #endif
 
diff --git a/unicorn/src/CgtMain.cpp b/unicorn/src/CgtMain.cpp
index 4070bdeb..1fb4113d 100644
--- a/unicorn/src/CgtMain.cpp
+++ b/unicorn/src/CgtMain.cpp
@@ -36,7 +36,7 @@ namespace bopts = boost::program_options;
 #include <QtGui>
 #if (QT_VERSION >= QT_VERSION_CHECK(4,5,0)) and \
     (QT_VERSION <  QT_VERSION_CHECK(5,0,0)) and \
-    not defined (__APPLE__)
+    not defined (__APPLE__) and not defined (__CYGWIN__) 
 #  include  <QGtkStyle>
 #endif
 
@@ -319,7 +319,7 @@ int main ( int argc, char *argv[] )
       auto_ptr<QApplication> qa ( new HApplication(argc,argv) );
 #if (QT_VERSION >= QT_VERSION_CHECK(4,5,0)) and \
     (QT_VERSION <  QT_VERSION_CHECK(5,0,0)) and \
-    not defined (__APPLE__)
+    not defined (__APPLE__) and not defined (__CYGWIN__)
       qa->setStyle ( new QGtkStyle() );
 #endif
       Graphics::enable ();
diff --git a/vlsisapd/src/configuration/src/ConfEditorMain.cpp b/vlsisapd/src/configuration/src/ConfEditorMain.cpp
index 52507dbd..5f64af49 100644
--- a/vlsisapd/src/configuration/src/ConfEditorMain.cpp
+++ b/vlsisapd/src/configuration/src/ConfEditorMain.cpp
@@ -26,7 +26,7 @@ namespace boptions = boost::program_options;
 #include  <QApplication>
 #if (QT_VERSION >= QT_VERSION_CHECK(4,5,0)) and \
     (QT_VERSION <  QT_VERSION_CHECK(5,0,0)) and \
-    not defined (__APPLE__)
+    not defined (__APPLE__) and not defined (__CYGWIN__)
 #  include  <QGtkStyle>
 #endif
 #include  "vlsisapd/utilities/Path.h"
@@ -66,7 +66,7 @@ int main ( int argc, char* argv[] )
     auto_ptr<QApplication> qa ( new QApplication(argc,argv) );
 #if (QT_VERSION >= QT_VERSION_CHECK(4,5,0)) and \
     (QT_VERSION <  QT_VERSION_CHECK(5,0,0)) and \
-    not defined (__APPLE__)
+    not defined (__APPLE__) and not defined (__CYGWIN__)
     if ( not disableGtkStyle ) qa->setStyle ( new QGtkStyle() );
 #endif