diff --git a/lib/Slic3r/GUI.pm b/lib/Slic3r/GUI.pm
index c4fe92a04..aea900028 100644
--- a/lib/Slic3r/GUI.pm
+++ b/lib/Slic3r/GUI.pm
@@ -60,6 +60,7 @@ our $no_controller;
 our $no_plater;
 our $mode;
 our $autosave;
+our $threads;
 our @cb;
 
 our $Settings = {
@@ -70,8 +71,8 @@ our $Settings = {
         invert_zoom => 0,
         background_processing => 0,
         # If set, the "Controller" tab for the control of the printer over serial line and the serial port settings are hidden.
-        # By default, Prusa has the controller hidden.
-        no_controller => 1,
+        no_controller => 0,
+        threads => $Slic3r::Config::Options->{threads}{default},
     },
 };
 
@@ -121,16 +122,15 @@ sub OnInit {
     my $last_version;
     if (-f "$enc_datadir/slic3r.ini") {
         my $ini = eval { Slic3r::Config->read_ini("$datadir/slic3r.ini") };
-        $Settings = $ini if $ini;
-        $last_version = $Settings->{_}{version};
-        $Settings->{_}{mode} ||= 'expert';
-        $Settings->{_}{autocenter} //= 1;
-        $Settings->{_}{invert_zoom} //= 0;
-        $Settings->{_}{background_processing} //= 1;
-        # If set, the "Controller" tab for the control of the printer over serial line and the serial port settings are hidden.
-        $Settings->{_}{no_controller} //= 1;
+        if ($ini) {
+            $last_version = $ini->{_}{version};
+            $ini->{_}{$_} = $Settings->{_}{$_}
+                for grep !exists $ini->{_}{$_}, keys %{$Settings->{_}};
+            $Settings = $ini;
+        }
     }
     $Settings->{_}{version} = $Slic3r::VERSION;
+    $Settings->{_}{threads} = $threads if $threads;
     $self->save_settings;
     
     # application frame
diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index d8d11f3e2..c62067371 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -1157,6 +1157,10 @@ sub start_background_process {
         return;
     }
     
+    if ($Slic3r::GUI::Settings->{_}{threads}) {
+        $self->{print}->config->set('threads', $Slic3r::GUI::Settings->{_}{threads});
+    }
+    
     # start thread
     @_ = ();
     $self->{process_thread} = Slic3r::spawn_thread(sub {
diff --git a/lib/Slic3r/GUI/Preferences.pm b/lib/Slic3r/GUI/Preferences.pm
index 91465fa64..231eb5cc9 100644
--- a/lib/Slic3r/GUI/Preferences.pm
+++ b/lib/Slic3r/GUI/Preferences.pm
@@ -67,6 +67,13 @@ sub new {
         default     => $Slic3r::GUI::Settings->{_}{background_processing},
         readonly    => !$Slic3r::have_threads,
     ));
+    $optgroup->append_single_option_line(Slic3r::GUI::OptionsGroup::Option->new(
+        opt_id      => 'threads',
+        type        => 'i',
+        label       => 'Threads',
+        tooltip     => $Slic3r::Config::Options->{threads}{tooltip},
+        default     => $Slic3r::GUI::Settings->{_}{threads},
+    ));
     $optgroup->append_single_option_line(Slic3r::GUI::OptionsGroup::Option->new(
         opt_id      => 'no_controller',
         type        => 'bool',
diff --git a/lib/Slic3r/GUI/Tab.pm b/lib/Slic3r/GUI/Tab.pm
index 6f772d2b7..a19bb1e76 100644
--- a/lib/Slic3r/GUI/Tab.pm
+++ b/lib/Slic3r/GUI/Tab.pm
@@ -497,7 +497,7 @@ sub build {
         external_perimeter_extrusion_width infill_extrusion_width solid_infill_extrusion_width 
         top_infill_extrusion_width support_material_extrusion_width
         infill_overlap bridge_flow_ratio
-        xy_size_compensation threads resolution
+        xy_size_compensation resolution
     ));
     $self->{config}->set('print_settings_id', '');
     
@@ -686,7 +686,6 @@ sub build {
         {
             my $optgroup = $page->new_optgroup('Other');
             $optgroup->append_single_option_line('xy_size_compensation');
-            $optgroup->append_single_option_line('threads') if $Slic3r::have_threads;
             $optgroup->append_single_option_line('resolution');
         }
     }
diff --git a/lib/Slic3r/Print/Simple.pm b/lib/Slic3r/Print/Simple.pm
index 9087ae0bc..26f1d4383 100644
--- a/lib/Slic3r/Print/Simple.pm
+++ b/lib/Slic3r/Print/Simple.pm
@@ -14,7 +14,7 @@ use Slic3r::Geometry::Clipper qw(diff);
 has '_print' => (
     is      => 'ro',
     default => sub { Slic3r::Print->new },
-    handles => [qw(apply_config extruders output_filepath
+    handles => [qw(apply_config config extruders output_filepath
                     total_used_filament total_extruded_volume
                     placeholder_parser process)],
 );
diff --git a/slic3r.pl b/slic3r.pl
index d4ebd5c48..69bb58593 100755
--- a/slic3r.pl
+++ b/slic3r.pl
@@ -29,6 +29,7 @@ my %cli_options = ();
         'debug'                 => \$Slic3r::debug,
         'gui'                   => \$opt{gui},
         'o|output=s'            => \$opt{output},
+        'j|threads=i'           => \$opt{threads},
         
         'save=s'                => \$opt{save},
         'load=s@'               => \$opt{load},
@@ -109,6 +110,7 @@ if ((!@ARGV || $opt{gui}) && !$opt{save} && eval "require Slic3r::GUI; 1") {
         $Slic3r::GUI::no_plater     = $opt{no_plater};
         $Slic3r::GUI::mode          = $opt{gui_mode};
         $Slic3r::GUI::autosave      = $opt{autosave};
+        $Slic3r::GUI::threads       = $opt{threads};
     }
     $gui = Slic3r::GUI->new;
     setlocale(LC_NUMERIC, 'C');
@@ -263,6 +265,7 @@ if (@ARGV) {  # slicing from command line
         );
         
         $sprint->apply_config($config);
+        $sprint->config->set('threads', $opt{threads}) if $opt{threads};
         $sprint->set_model($model);
         
         if ($opt{export_svg}) {
@@ -293,7 +296,7 @@ sub usage {
     my $j = '';
     if ($Slic3r::have_threads) {
         $j = <<"EOF";
-    -j, --threads <num> Number of threads to use (1+, default: $config->{threads})
+    -j, --threads <num> Number of threads to use
 EOF
     }
     
diff --git a/xs/src/libslic3r/PrintConfig.cpp b/xs/src/libslic3r/PrintConfig.cpp
index 586661510..1766f63cd 100644
--- a/xs/src/libslic3r/PrintConfig.cpp
+++ b/xs/src/libslic3r/PrintConfig.cpp
@@ -1383,7 +1383,6 @@ PrintConfigDef::PrintConfigDef()
     def = this->add("threads", coInt);
     def->label = "Threads";
     def->tooltip = "Threads are used to parallelize long-running tasks. Optimal threads number is slightly above the number of available cores/processors.";
-    def->cli = "threads|j=i";
     def->readonly = true;
     def->min = 1;
     {
diff --git a/xs/src/libslic3r/PrintConfig.hpp b/xs/src/libslic3r/PrintConfig.hpp
index bd63bb919..2ea423d8c 100644
--- a/xs/src/libslic3r/PrintConfig.hpp
+++ b/xs/src/libslic3r/PrintConfig.hpp
@@ -624,6 +624,7 @@ class CLIConfig
     ConfigOptionString              save;
     ConfigOptionFloat               scale;
     ConfigOptionPoint3              scale_to_fit;
+    ConfigOptionBool                threads;
     
     CLIConfig() : ConfigBase(), StaticConfig() {
         this->def = &cli_config_def;
@@ -647,6 +648,7 @@ class CLIConfig
         OPT_PTR(save);
         OPT_PTR(scale);
         OPT_PTR(scale_to_fit);
+        OPT_PTR(threads);
         
         return NULL;
     };