diff --git a/gui/gui/inc/TGMimeTypes.h b/gui/gui/inc/TGMimeTypes.h
index 226989d7fb30b385931a53b09af13fa4166701d1..531ee8bdbbcc78125a7c1a67f1d6bac1a9d43e68 100644
--- a/gui/gui/inc/TGMimeTypes.h
+++ b/gui/gui/inc/TGMimeTypes.h
@@ -46,6 +46,7 @@ private:
    TRegexp  *fReg;        // pattern regular expression
 
 public:
+   TGMime() : fReg(0) {}
    ~TGMime();
 };