diff --git a/R/RunModel_Lag.R b/R/RunModel_Lag.R
index 622139ade5c150ee55c7918acc4e5278497208af..be71d890fc117ec75e3a6c0461bd937eb7911ef8 100644
--- a/R/RunModel_Lag.R
+++ b/R/RunModel_Lag.R
@@ -81,7 +81,7 @@ RunModel_Lag <- function(InputsModel, RunOptions, Param, QcontribDown) {
           # If warm-up period is not enough long complete beginning with first value
           ini <- c(rep(ini[1], floor(PT[iUpBasins] + 1) - length(ini)), ini)
         }
-        return(ini)
+        return(as.vector(ini))
       }
     )
   }