diff --git a/src/callback.c b/src/callback.c
index fdd248b6..c88b4c8a 100644
--- a/src/callback.c
+++ b/src/callback.c
@@ -2442,6 +2442,11 @@ int rstate; /* (reduced state, without ShiftMask) */
 
       dbg(1, "callback(): -------------\n");
     }
+    else {
+       if(has_x) tcleval("alert_ {Can not write into the netlist directory. Please check} {}");
+       else dbg(0, "Can not write into the netlist directory. Please check");
+       err = 1;
+    }
     if(err) {
       if(has_x) {
         tclvareval(xctx->top_path, ".menubar.netlist configure -bg red", NULL);
diff --git a/src/scheduler.c b/src/scheduler.c
index 16ff0fe5..7f846db5 100644
--- a/src/scheduler.c
+++ b/src/scheduler.c
@@ -775,7 +775,7 @@ int xschem(ClientData clientdata, Tcl_Interp *interp, int argc, const char * arg
       }
     }
 
-    /* exit [closewindow]
+    /* exit [closewindow] [force]
      *   Exit the program, ask for confirm if current file modified.
      *   if 'closewindow' is given close the window, otherwise leave with a blank schematic
      *   when closing the last remaining window
@@ -2704,6 +2704,11 @@ int xschem(ClientData clientdata, Tcl_Interp *interp, int argc, const char * arg
          Tcl_SetResult(interp, my_itoa(err), TCL_VOLATILE);
         }
       }
+      else {
+         if(has_x) tcleval("alert_ {Can not write into the netlist directory. Please check} {}");
+         else dbg(0, "Can not write into the netlist directory. Please check");
+         err = 1;
+      }
       if(err) {
         if(has_x) {
           tclvareval(xctx->top_path, ".menubar.netlist configure -bg red", NULL);
diff --git a/src/xschem.tcl b/src/xschem.tcl
index b5f9e1cf..c02d864f 100644
--- a/src/xschem.tcl
+++ b/src/xschem.tcl
@@ -1799,61 +1799,46 @@ proc simulate {{callback {}}} {
       set fg {execute}
     }
     set cmd [subst -nobackslashes $sim($tool,$def,cmd)]
-    if {$OS == "Windows"} {
-      # $cmd cannot be surrounded by {} as exec will change forward slash to backward slash
-      set save [pwd]
-      cd $netlist_dir
-      set_simulate_button list [xschem get top_path] [xschem get current_win_path]
-      if { $callback ne {} } {
-        uplevel #0 {
-          eval $callback
-        }
-      }
-      #eval exec {cmd /V /C "cd $netlist_dir&&$cmd}
-      eval exec $cmd &
-      cd $save
-      set id 0
-    } else {
-      # window interface       tabbed interface
-      # -----------------------------------------
-      # top_path   win_path    top_path   win_path
-      #  {}        .drw         {}        .drw
-      #  .x1       .x1.drw      {}        .x1.drw
-      #  .x2       .x2.drw      {}        .x2.drw
-      set execute(callback) "
-         set_simulate_button [list [xschem get top_path] [xschem get current_win_path]]
-         $callback
-      "
-      # puts $cmd
-
-      if {$fg eq {execute_wait}} {xschem set semaphore [expr {[xschem get semaphore] +1}]}
-
-      set save [pwd]
-      cd $netlist_dir
-      set id [eval execute $st $cmd]   ;# Start simulation process
-      cd $save
-
-      if {[info exists has_x] && $id >= 0 } {
-        set tctx::[xschem get current_win_path]_simulate_id $id
-        set button_path [xschem get top_path].menubar.simulate
-        $button_path configure -bg yellow
-        set tctx::[xschem get current_win_path]_simulate yellow
-      }
-
-      puts "Simulation started: execution ID: $id"
-
-      if {$fg eq {execute_wait}} {
-        if {$id >= 0} {
-          vwait execute(pipe,$id)
-        }
-        xschem set semaphore [expr {[xschem get semaphore] -1}]
+    
+    # window interface       tabbed interface
+    # -----------------------------------------
+    # top_path   win_path    top_path   win_path
+    #  {}        .drw         {}        .drw
+    #  .x1       .x1.drw      {}        .x1.drw
+    #  .x2       .x2.drw      {}        .x2.drw
+    set execute(callback) "
+       set_simulate_button [list [xschem get top_path] [xschem get current_win_path]]
+       $callback
+    "
+    # puts $cmd
+
+    if {$fg eq {execute_wait}} {xschem set semaphore [expr {[xschem get semaphore] +1}]}
+
+    set save [pwd]
+    cd $netlist_dir
+    # Note: Windows $cmd cannot be surrounded by {} as exec will change forward slash to backward slash
+    set id [eval execute $st $cmd]   ;# Start simulation process
+    cd $save
+
+    if {[info exists has_x] && $id >= 0 } {
+      set tctx::[xschem get current_win_path]_simulate_id $id
+      set button_path [xschem get top_path].menubar.simulate
+      $button_path configure -bg yellow
+      set tctx::[xschem get current_win_path]_simulate yellow
+    }
+
+    puts "Simulation started: execution ID: $id"
+
+    if {$fg eq {execute_wait}} {
+      if {$id >= 0} {
+        vwait execute(pipe,$id)
       }
+      xschem set semaphore [expr {[xschem get semaphore] -1}]
     }
     return $id
   } else {
     return -1
   }
-  
 }
 
 proc gaw_echoline {} {
diff --git a/tests/create_save.tcl b/tests/create_save.tcl
index ac3df64c..61664bb6 100644
--- a/tests/create_save.tcl
+++ b/tests/create_save.tcl
@@ -47,7 +47,7 @@ proc create_save {} {
           close $fd
           set filename [regsub {\.tcl$} $f {}]
           set output ${filename}_debug.txt
-          if {[catch {eval exec {$xschem_cmd ${results_dir}/$fn_sch -d 1 --script ${testname}/tests/${f} 2> ${results_dir}/$output}} msg]} {
+          if {[catch {eval exec {$xschem_cmd ${results_dir}/$fn_sch --pipe -d 1 --script ${testname}/tests/${f} 2> ${results_dir}/$output}} msg]} {
             puts "FATAL: $msg"
             incr num_fatals
           } else {
diff --git a/tests/run_regression.tcl b/tests/run_regression.tcl
index ecf3ada7..c5f46127 100644
--- a/tests/run_regression.tcl
+++ b/tests/run_regression.tcl
@@ -57,4 +57,4 @@ foreach tc $tcases {
 }
 
 source test_utility.tcl
-exec $xschem_cmd --pipe -q --script xschemtest.tcl 2>&1 > stefan_xschemtest.log
\ No newline at end of file
+exec $xschem_cmd --pipe -q --script xschemtest.tcl > stefan_xschemtest.log 2>@1