diff --git a/xs/src/libslic3r/Config.cpp b/xs/src/libslic3r/Config.cpp
index da33b2fcd..abcc4afc1 100644
--- a/xs/src/libslic3r/Config.cpp
+++ b/xs/src/libslic3r/Config.cpp
@@ -256,7 +256,7 @@ ConfigBase::apply_only(const ConfigBase &other, const t_config_option_keys &opt_
     for (const t_config_option_key &opt_key : opt_keys) {
         ConfigOption* my_opt = this->option(opt_key, true);
         if (my_opt == NULL) {
-            if (ignore_nonexistent == false) throw "Attempt to apply non-existent option";
+            if (ignore_nonexistent == false) throw UnknownOptionException();
             continue;
         }
         
@@ -339,7 +339,7 @@ ConfigBase::get_abs_value(const t_config_option_key &opt_key) const {
     } else if (const ConfigOptionFloat* optv = dynamic_cast<const ConfigOptionFloat*>(opt)) {
         return optv->value;
     } else {
-        throw "Not a valid option type for get_abs_value()";
+        throw std::runtime_error("Not a valid option type for get_abs_value()");
     }
 }
 
@@ -487,7 +487,7 @@ DynamicConfig::optptr(const t_config_option_key &opt_key, bool create) {
                 optv->keys_map = &optdef->enum_keys_map;
                 opt = static_cast<ConfigOption*>(optv);
             } else {
-                throw "Unknown option type";
+                throw std::runtime_error("Unknown option type");
             }
             this->options[opt_key] = opt;
             return opt;
diff --git a/xs/src/libslic3r/Model.cpp b/xs/src/libslic3r/Model.cpp
index d3127f917..d3393250e 100644
--- a/xs/src/libslic3r/Model.cpp
+++ b/xs/src/libslic3r/Model.cpp
@@ -349,8 +349,8 @@ Model::duplicate_objects(size_t copies_num, coordf_t dist, const BoundingBoxf* b
 void
 Model::duplicate_objects_grid(size_t x, size_t y, coordf_t dist)
 {
-    if (this->objects.size() > 1) throw "Grid duplication is not supported with multiple objects";
-    if (this->objects.empty()) throw "No objects!";
+    if (this->objects.size() > 1) throw std::runtime_error("Grid duplication is not supported with multiple objects");
+    if (this->objects.empty()) throw std::runtime_error("No objects!");
 
     ModelObject* object = this->objects.front();
     object->clear_instances();