diff --git a/R/fit_mnhmm.R b/R/fit_mnhmm.R
index 9af6a40..a123af6 100644
--- a/R/fit_mnhmm.R
+++ b/R/fit_mnhmm.R
@@ -215,11 +215,12 @@ fit_mnhmm <- function(model, inits, init_sd, restarts, lambda, method,
     logliks <- -unlist(lapply(out, "[[", "objective")) * n_obs
     return_codes <- unlist(lapply(out, "[[", "status"))
     successful <- which(return_codes > 0)
-    stopifnot_(
-      length(successful) > 0,
-      c("All optimizations terminated due to error.",
-        "Error of first restart: ", error_msg(return_codes[1]))
-    ) 
+    if (length(successful) == 0) {
+      warning_(
+        c("All optimizations terminated due to error.",
+          "Error of first restart: ", error_msg(return_codes[1]))
+      )
+    }
     optimum <- successful[which.max(logliks[successful])]
     init <- out[[optimum]]$solution
     if (save_all_solutions) {
@@ -235,10 +236,11 @@ fit_mnhmm <- function(model, inits, init_sd, restarts, lambda, method,
     opts = control
   )
   end_time <- proc.time()
-  stopifnot_(
-    out$status >= 0,
-    paste("Optimization terminated due to error:", error_msg(out$status))
-  )
+  if (out$status < 0) {
+    warning_(
+      paste("Optimization terminated due to error:", error_msg(out$status))
+    )
+  }
   pars <- out$solution
   model$etas$pi <- create_eta_pi_mnhmm(
     pars[seq_len(n_i)], S, K_pi, D
diff --git a/R/fit_nhmm.R b/R/fit_nhmm.R
index 2e64b49..7953025 100644
--- a/R/fit_nhmm.R
+++ b/R/fit_nhmm.R
@@ -167,11 +167,12 @@ fit_nhmm <- function(model, inits, init_sd, restarts, lambda, method, pseudocoun
       logliks <- -unlist(lapply(out, "[[", "objective")) * n_obs
       return_codes <- unlist(lapply(out, "[[", "status"))
       successful <- which(return_codes > 0)
-      stopifnot_(
-        length(successful) > 0,
-        c("All optimizations terminated due to error.",
-          "Error of first restart: ", error_msg(return_codes[1]))
-      ) 
+      if (length(successful) == 0) {
+        warning_(
+          c("All optimizations terminated due to error.",
+            "Error of first restart: ", error_msg(return_codes[1]))
+        )
+      }
       optimum <- successful[which.max(logliks[successful])]
       init <- out[[optimum]]$solution
       if (save_all_solutions) {
@@ -188,10 +189,11 @@ fit_nhmm <- function(model, inits, init_sd, restarts, lambda, method, pseudocoun
       opts = control
     )
     end_time <- proc.time()
-    stopifnot_(
-      out$status >= 0,
-      paste("Optimization terminated due to error:", error_msg(out$status))
-    )
+    if (out$status < 0) {
+      warning_(
+        paste("Optimization terminated due to error:", error_msg(out$status))
+      )
+    }
     
     pars <- out$solution
     model$etas$pi <- create_eta_pi_nhmm(pars[seq_len(n_i)], S, K_pi)
@@ -255,11 +257,12 @@ fit_nhmm <- function(model, inits, init_sd, restarts, lambda, method, pseudocoun
       },
       future.seed = TRUE)
       return_codes <- unlist(lapply(out, "[[", "return_code"))
-      stopifnot_(
-        any(return_codes == 0),
-        c("All optimizations terminated due to error.",
-        "Error of first restart: ", error_msg(return_codes[1]))
-      ) 
+      if (all(return_codes < 0)) {
+        warning_(
+          c("All optimizations terminated due to error.",
+            "Error of first restart: ", error_msg(return_codes[1]))
+        )
+      }
       logliks <- unlist(lapply(out, "[[", "penalized_logLik")) * n_obs
       optimum <- out[[which.max(logliks)]]
       init <- stats::setNames(
@@ -297,11 +300,11 @@ fit_nhmm <- function(model, inits, init_sd, restarts, lambda, method, pseudocoun
         control_mstep$print_level, lambda, pseudocount)
     }
     end_time <- proc.time()
-    stopifnot_(
-      out$return_code == 0,
-      paste("Optimization terminated due to error:", error_msg(out$return_code))
-    )
-    
+    if (out$return_code < 0) {
+      warning_(
+        paste("Optimization terminated due to error:", error_msg(out$return_code))
+      )
+    }
     model$etas$pi[] <- out$eta_pi
     model$gammas$pi <- eta_to_gamma_mat(model$etas$pi)
     model$etas$A <- out$eta_A
diff --git a/R/utilities.R b/R/utilities.R
index 5ca26ad..1c99c51 100644
--- a/R/utilities.R
+++ b/R/utilities.R
@@ -144,12 +144,10 @@ create_emissionArray <- function(model) {
 #' Convert error message to text
 #' @noRd
 error_msg <- function(error) {
-  gamma <- dplyr::case_when(
-    error %in% c(-(1:4)) ~ "",
-    error %in% c(1, -(101:104)) ~ "gamma_pi",
-    error %in% c(2, -(201:204)) ~ "gamma_A",
-    error == 3 | error %in% -301:-304 ~ "gamma_B"
-  )
+  
+  if (error %in% c(1, -(101:104))) gamma <- "gamma_pi"
+  if (error %in% c(2, -(201:204))) gamma <- "gamma_A"
+  if (error %in% c(3, -(301:304))) gamma <- "gamma_B"
   
   nonfinite_msg <- paste0(
     "Error: Some of the values in ", gamma, " are nonfinite, likely due to ",
@@ -162,22 +160,29 @@ error_msg <- function(error) {
   }
   
   e <- seq(0, 300, by = 100)
-  msg <- dplyr::case_when(
-    error %in% 1:3 ~ nonfinite_msg,
-    error %in% (-1 - e) ~ paste0(
-      mstep, "NLOPT_FAILURE: Generic failure code."
-    ),
-    error %in% (-2 - e) ~ paste0(
-      mstep, "NLOPT_INVALID_ARGS: Invalid arguments (e.g., lower bounds are ",
+  if (error %in% 1:3) {
+    msg <- nonfinite_msg
+  }
+  if (error %in% (-1 - e)) {
+    msg <- paste0(mstep, "NLOPT_FAILURE: Generic failure code.")
+  }
+  if (error %in% (-2 - e)) {
+    msg <- paste0(
+      mstep, 
+      "NLOPT_INVALID_ARGS: Invalid arguments (e.g., lower bounds are ",
       "bigger than upper bounds, an unknown algorithm was specified)."
-    ),
-    error %in% (-3 - e) ~ paste0(
+    )
+  }
+  if (error %in% (-3 - e)) {
+    msg <- paste0(
       mstep, "NLOPT_OUT_OF_MEMORY: Ran out of memory."
-    ),
-    error %in% (-4 - e) ~ paste0(
-      mstep, 
+    )
+  }
+  if (error %in% (-4 - e)) {
+    msg <- paste0(
+      mstep,
       "NLOPT_ROUNDOFF_LIMITED: Halted because roundoff errors limited progress."
     )
-  )
+  }
   msg
 }
\ No newline at end of file
diff --git a/src/nhmm_EM.cpp b/src/nhmm_EM.cpp
index 7e972ec..a67107a 100644
--- a/src/nhmm_EM.cpp
+++ b/src/nhmm_EM.cpp
@@ -12,7 +12,7 @@ double nhmm_base::objective_pi(const arma::vec& x, arma::vec& grad) {
   mstep_iter++;
   
   double value = 0;
- 
+  
   eta_pi = arma::mat(x.memptr(), S - 1, K_pi);
   gamma_pi = sum_to_zero(eta_pi, Qs);
   arma::mat tmpgrad(S, K_pi, arma::fill::zeros);
@@ -602,7 +602,17 @@ Rcpp::List EM_LBFGS_nhmm_singlechannel(
     if (model.mstep_error_code != 0) {
       return Rcpp::List::create(
         Rcpp::Named("return_code") = model.mstep_error_code,
-        Rcpp::Named("penalized_logLik") = arma::datum::nan
+        Rcpp::Named("eta_pi") = Rcpp::wrap(model.eta_pi),
+        Rcpp::Named("eta_A") = Rcpp::wrap(model.eta_A),
+        Rcpp::Named("eta_B") = Rcpp::wrap(model.eta_B),
+        Rcpp::Named("penalized_logLik") = arma::datum::nan,
+        Rcpp::Named("penalty_term") = arma::datum::nan,
+        Rcpp::Named("logLik") = arma::datum::nan,
+        Rcpp::Named("iterations") = iter,
+        Rcpp::Named("relative_f_change") = relative_change,
+        Rcpp::Named("absolute_f_change") = absolute_change,
+        Rcpp::Named("absolute_x_change") = absolute_x_change,
+        Rcpp::Named("relative_x_change") = relative_x_change
       );
     }
     model.mstep_A(
@@ -611,7 +621,17 @@ Rcpp::List EM_LBFGS_nhmm_singlechannel(
     if (model.mstep_error_code != 0) {
       return Rcpp::List::create(
         Rcpp::Named("return_code") = model.mstep_error_code,
-        Rcpp::Named("penalized_logLik") = arma::datum::nan
+        Rcpp::Named("eta_pi") = Rcpp::wrap(model.eta_pi),
+        Rcpp::Named("eta_A") = Rcpp::wrap(model.eta_A),
+        Rcpp::Named("eta_B") = Rcpp::wrap(model.eta_B),
+        Rcpp::Named("penalized_logLik") = arma::datum::nan,
+        Rcpp::Named("penalty_term") = arma::datum::nan,
+        Rcpp::Named("logLik") = arma::datum::nan,
+        Rcpp::Named("iterations") = iter,
+        Rcpp::Named("relative_f_change") = relative_change,
+        Rcpp::Named("absolute_f_change") = absolute_change,
+        Rcpp::Named("absolute_x_change") = absolute_x_change,
+        Rcpp::Named("relative_x_change") = relative_x_change
       );
     }
     model.mstep_B(
@@ -620,7 +640,17 @@ Rcpp::List EM_LBFGS_nhmm_singlechannel(
     if (model.mstep_error_code != 0) {
       return Rcpp::List::create(
         Rcpp::Named("return_code") = model.mstep_error_code,
-        Rcpp::Named("penalized_logLik") = arma::datum::nan
+        Rcpp::Named("eta_pi") = Rcpp::wrap(model.eta_pi),
+        Rcpp::Named("eta_A") = Rcpp::wrap(model.eta_A),
+        Rcpp::Named("eta_B") = Rcpp::wrap(model.eta_B),
+        Rcpp::Named("penalized_logLik") = arma::datum::nan,
+        Rcpp::Named("penalty_term") = arma::datum::nan,
+        Rcpp::Named("logLik") = arma::datum::nan,
+        Rcpp::Named("iterations") = iter,
+        Rcpp::Named("relative_f_change") = relative_change,
+        Rcpp::Named("absolute_f_change") = absolute_change,
+        Rcpp::Named("absolute_x_change") = absolute_x_change,
+        Rcpp::Named("relative_x_change") = relative_x_change
       );
     }
     // Update model
@@ -795,7 +825,17 @@ Rcpp::List EM_LBFGS_nhmm_multichannel(
     if (model.mstep_error_code != 0) {
       return Rcpp::List::create(
         Rcpp::Named("return_code") = model.mstep_error_code,
-        Rcpp::Named("penalized_logLik") = arma::datum::nan
+        Rcpp::Named("eta_pi") = Rcpp::wrap(model.eta_pi),
+        Rcpp::Named("eta_A") = Rcpp::wrap(model.eta_A),
+        Rcpp::Named("eta_B") = Rcpp::wrap(model.eta_B),
+        Rcpp::Named("penalized_logLik") = arma::datum::nan,
+        Rcpp::Named("penalty_term") = arma::datum::nan,
+        Rcpp::Named("logLik") = arma::datum::nan,
+        Rcpp::Named("iterations") = iter,
+        Rcpp::Named("relative_f_change") = relative_change,
+        Rcpp::Named("absolute_f_change") = absolute_change,
+        Rcpp::Named("absolute_x_change") = absolute_x_change,
+        Rcpp::Named("relative_x_change") = relative_x_change
       );
     }
     model.mstep_A(
@@ -804,7 +844,17 @@ Rcpp::List EM_LBFGS_nhmm_multichannel(
     if (model.mstep_error_code != 0) {
       return Rcpp::List::create(
         Rcpp::Named("return_code") = model.mstep_error_code,
-        Rcpp::Named("penalized_logLik") = arma::datum::nan
+        Rcpp::Named("eta_pi") = Rcpp::wrap(model.eta_pi),
+        Rcpp::Named("eta_A") = Rcpp::wrap(model.eta_A),
+        Rcpp::Named("eta_B") = Rcpp::wrap(model.eta_B),
+        Rcpp::Named("penalized_logLik") = arma::datum::nan,
+        Rcpp::Named("penalty_term") = arma::datum::nan,
+        Rcpp::Named("logLik") = arma::datum::nan,
+        Rcpp::Named("iterations") = iter,
+        Rcpp::Named("relative_f_change") = relative_change,
+        Rcpp::Named("absolute_f_change") = absolute_change,
+        Rcpp::Named("absolute_x_change") = absolute_x_change,
+        Rcpp::Named("relative_x_change") = relative_x_change
       );
     }
     model.mstep_B(
@@ -813,7 +863,17 @@ Rcpp::List EM_LBFGS_nhmm_multichannel(
     if (model.mstep_error_code != 0) {
       return Rcpp::List::create(
         Rcpp::Named("return_code") = model.mstep_error_code,
-        Rcpp::Named("penalized_logLik") = arma::datum::nan
+        Rcpp::Named("eta_pi") = Rcpp::wrap(model.eta_pi),
+        Rcpp::Named("eta_A") = Rcpp::wrap(model.eta_A),
+        Rcpp::Named("eta_B") = Rcpp::wrap(model.eta_B),
+        Rcpp::Named("penalized_logLik") = arma::datum::nan,
+        Rcpp::Named("penalty_term") = arma::datum::nan,
+        Rcpp::Named("logLik") = arma::datum::nan,
+        Rcpp::Named("iterations") = iter,
+        Rcpp::Named("relative_f_change") = relative_change,
+        Rcpp::Named("absolute_f_change") = absolute_change,
+        Rcpp::Named("absolute_x_change") = absolute_x_change,
+        Rcpp::Named("relative_x_change") = relative_x_change
       );
     }
     // Update model