diff --git a/src/include/PRunBase.h b/src/include/PRunBase.h
index ccf83a2c..d3dcd5f5 100644
--- a/src/include/PRunBase.h
+++ b/src/include/PRunBase.h
@@ -79,7 +79,7 @@ class PRunBase
 
     EPMusrHandleTag fHandleTag; ///< tag telling whether this is used for fit, view, ...
 
-    unsigned int fRunNo;        ///< number of the run within the msr file
+    int fRunNo;                 ///< number of the run within the msr file
     PMsrHandler      *fMsrInfo; ///< msr-file handler
     PMsrRunStructure *fRunInfo; ///< run info used to filter out needed infos for the run
     PRunDataHandler  *fRawData; ///< holds the raw run data