diff --git a/cpp/dataio/poswriter.cpp b/cpp/dataio/poswriter.cpp
index c4ce2060c..eabbe9633 100644
--- a/cpp/dataio/poswriter.cpp
+++ b/cpp/dataio/poswriter.cpp
@@ -53,7 +53,7 @@ static void writeLoop(
     if(!suc)
       break;
 
-    if(out == NULL || numWrittenThisFile > maxPosesPerOutFile) {
+    if(out == NULL || numWrittenThisFile >= maxPosesPerOutFile) {
       if(out != NULL) {
         out->close();
         delete out;