diff --git a/src/fix_ave_time.cpp b/src/fix_ave_time.cpp
index 90bef7dc65..9b8dd13f05 100644
--- a/src/fix_ave_time.cpp
+++ b/src/fix_ave_time.cpp
@@ -910,7 +910,8 @@ void FixAveTime::invoke_vector(bigint ntimestep)
     fflush(fp);
     if (overwrite) {
       long fileend = ftell(fp);
-      if (fileend > 0) ftruncate(fileno(fp),fileend);
+      if ((fileend > 0) && (ftruncate(fileno(fp),fileend)))
+        perror("Error while tuncating output");
     }
   }
 }