diff --git a/R/ErrorCrit_RMSE.R b/R/ErrorCrit_RMSE.R
index 6cab33bc57147355c0603f6cfd86daf8904c1bee..ce1b78fe09e7880cea9cb744013b9dd279815dca 100644
--- a/R/ErrorCrit_RMSE.R
+++ b/R/ErrorCrit_RMSE.R
@@ -1,19 +1,22 @@
 ErrorCrit_RMSE <- function(InputsCrit, OutputsModel, warnings = TRUE, verbose = TRUE) {
-  
+
   ## Arguments check
   if (!inherits(OutputsModel, "OutputsModel")) {
     stop("'OutputsModel' must be of class 'OutputsModel'")
   }
-  
+  if (!inherits(InputsCrit, "Single")) {
+    stop("'ErrorCrit_RMSE' can only be used with 'InputsCrit' of class 'Single'")
+  }
+
   EC <- .ErrorCrit(InputsCrit = InputsCrit, Crit = "RMSE",  OutputsModel = OutputsModel, warnings = warnings)
-  
+
   CritValue <- NA
-  
+
   if (EC$CritCompute) {
     ## ErrorCrit
     Numer <- sum((EC$VarSim - EC$VarObs)^2, na.rm = TRUE)
     Denom <- sum(!is.na(EC$VarObs))
-    
+
     if (Numer == 0) {
       Crit <- 0
     } else {
@@ -22,22 +25,22 @@ ErrorCrit_RMSE <- function(InputsCrit, OutputsModel, warnings = TRUE, verbose =
     if (is.numeric(Crit) & is.finite(Crit)) {
       CritValue <- Crit
     }
-    
+
     ## Verbose
     if (verbose) {
       message(sprintf("Crit. %s = %.4f", EC$CritName, CritValue))
     }
   }
-  
-  
+
+
   ## Output
   OutputsCrit <- list(CritValue       = CritValue,
                       CritName        = EC$CritName,
                       CritBestValue   = EC$CritBestValue,
                       Multiplier      = EC$Multiplier,
                       Ind_notcomputed = EC$Ind_TS_ignore)
-  
+
   class(OutputsCrit) <- c("RMSE", "ErrorCrit")
   return(OutputsCrit)
-  
+
 }
diff --git a/R/UtilsErrorCrit.R b/R/UtilsErrorCrit.R
index 4e200bb28ec42c6378c4ab75ab7cfb59868a66ca..89b4e25fdb440b20683f45006a01a4a60a28c987 100644
--- a/R/UtilsErrorCrit.R
+++ b/R/UtilsErrorCrit.R
@@ -9,11 +9,7 @@
     stop("'InputsCrit' must be of class 'InputsCrit'", call. = FALSE)
   }
   if (inherits(InputsCrit, "Multi") | inherits(InputsCrit, "Compo")) {
-    if (Crit == "RMSE") {
-      stop("'InputsCrit' must be of class 'Single'. Use the 'ErrorCrit' function on objects of class 'Multi' with RMSE", call. = FALSE)
-    } else {
-      stop(paste0("'InputsCrit' must be of class 'Single'. Use the 'ErrorCrit' function on objects of class 'Multi' or 'Compo' with ", Crit), call. = FALSE)
-    }
+    stop(paste0("'InputsCrit' must be of class 'Single'. Use the 'ErrorCrit' function on objects of class 'Multi' or 'Compo' with ", Crit), call. = FALSE)
   }