diff --git a/lib/Slic3r/Config.pm b/lib/Slic3r/Config.pm
index 167c733dd..930917dfd 100644
--- a/lib/Slic3r/Config.pm
+++ b/lib/Slic3r/Config.pm
@@ -269,12 +269,6 @@ sub validate {
                 qw(perimeter infill solid_infill top_infill support_material first_layer);
     }
     
-    # support material
-    if ($self->support_material) {
-        die "Value of 0 is illegal. Use some % value instead (e.g. 150%) for auto.\n"
-            if $self->support_material_threshold =~ /^0+/;
-    }
-    
     
     # general validation, quick and dirty
     foreach my $opt_key (@{$self->get_keys}) {
diff --git a/xs/src/libslic3r/PrintConfig.cpp b/xs/src/libslic3r/PrintConfig.cpp
index 8a63ef268..e0771d596 100644
--- a/xs/src/libslic3r/PrintConfig.cpp
+++ b/xs/src/libslic3r/PrintConfig.cpp
@@ -1705,6 +1705,10 @@ PrintConfigBase::_handle_legacy(t_config_option_key &opt_key, std::string &value
             values is a dirty hack and will need to be removed sometime in the future, but it
             will avoid lots of complaints for now. */
         value = "0";
+    } else if (opt_key == "support_material_threshold" && value == "0") {
+        // 0 used to be automatic threshold, but we introduced percent values so let's
+        // transform it into the default value
+        value = "60%";
     }
     
     // cemetery of old config settings