diff --git a/src/gui/query/apply_sort_query.h b/src/gui/query/apply_sort_query.h
index 4123c57e..e3eafda5 100644
--- a/src/gui/query/apply_sort_query.h
+++ b/src/gui/query/apply_sort_query.h
@@ -33,16 +33,17 @@ public:
   ApplySortQuery(LootState& state, const std::vector<std::string>& plugins) :
     state_(state), plugins_(plugins) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(trace) << "User has accepted sorted load order, applying it.";
     state_.decrementUnappliedChangeCounter();
     state_.getCurrentGame().SetLoadOrder(plugins_);
-    callback->Success("");
+
+    return "";
   }
 
 private:
   LootState& state_;
-  std::vector<std::string> plugins_;
+  const std::vector<std::string> plugins_;
 };
 }
 
diff --git a/src/gui/query/cancel_find_query.h b/src/gui/query/cancel_find_query.h
index f2b70450..70fbe1b4 100644
--- a/src/gui/query/cancel_find_query.h
+++ b/src/gui/query/cancel_find_query.h
@@ -34,13 +34,13 @@ class CancelFindQuery : public Query {
 public:
   CancelFindQuery(CefRefPtr<CefBrowser> browser) : browser_(browser) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     browser_->GetHost()->StopFinding(true);
-    callback->Success("");
+    return "";
   }
 
 private:
-  CefRefPtr<CefBrowser> browser_;
+  const CefRefPtr<CefBrowser> browser_;
 };
 }
 
diff --git a/src/gui/query/cancel_sort_query.h b/src/gui/query/cancel_sort_query.h
index ac32a4c8..b75dc7c7 100644
--- a/src/gui/query/cancel_sort_query.h
+++ b/src/gui/query/cancel_sort_query.h
@@ -36,12 +36,11 @@ public:
     MetadataQuery(state.getCurrentGame(), state.getLanguage().GetCode()),
     state_(state) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     state_.decrementUnappliedChangeCounter();
     state_.getCurrentGame().DecrementLoadOrderSortCount();
 
-    YAML::Node node(getGeneralMessages());
-    callback->Success(JSON::stringify(node));
+    return JSON::stringify(YAML::Node(getGeneralMessages()));
   }
 
 private:
diff --git a/src/gui/query/change_game_query.h b/src/gui/query/change_game_query.h
index e618fc11..dea40451 100644
--- a/src/gui/query/change_game_query.h
+++ b/src/gui/query/change_game_query.h
@@ -38,10 +38,10 @@ public:
     state_(state),
     gameFolder_(gameFolder) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     state_.changeGame(gameFolder_);
 
-    GetGameDataQuery::execute(callback);
+    return GetGameDataQuery::executeLogic();
   }
 
 private:
diff --git a/src/gui/query/clear_all_metadata_query.h b/src/gui/query/clear_all_metadata_query.h
index 231b517d..0eb8ff8e 100644
--- a/src/gui/query/clear_all_metadata_query.h
+++ b/src/gui/query/clear_all_metadata_query.h
@@ -36,7 +36,7 @@ public:
     MetadataQuery(state.getCurrentGame(), state.getLanguage().GetCode()),
     game_(state.getCurrentGame()) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(debug) << "Clearing all user metadata.";
 
     // Record which plugins have userlist entries.
@@ -47,7 +47,8 @@ public:
     game_.GetUserlist().Save(game_.UserlistPath());
 
     BOOST_LOG_TRIVIAL(trace) << "Rederiving display metadata for " << userlistPluginNames.size() << " plugins that had user metadata.";
-    callback->Success(getDerivedMetadataJson(userlistPluginNames));
+
+    return getDerivedMetadataJson(userlistPluginNames);
   }
 
 private:
diff --git a/src/gui/query/clear_plugin_metadata_query.h b/src/gui/query/clear_plugin_metadata_query.h
index 423ab51c..3aa16252 100644
--- a/src/gui/query/clear_plugin_metadata_query.h
+++ b/src/gui/query/clear_plugin_metadata_query.h
@@ -37,7 +37,7 @@ public:
     game_(state.getCurrentGame()),
     pluginName_(pluginName) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(debug) << "Clearing user metadata for plugin " << pluginName_;
 
     game_.GetUserlist().ErasePlugin(PluginMetadata(pluginName_));
@@ -46,14 +46,14 @@ public:
     // Now rederive the displayed metadata from the masterlist.
     YAML::Node derivedMetadata = generateDerivedMetadata(pluginName_);
     if (derivedMetadata.size() > 0)
-      callback->Success(JSON::stringify(derivedMetadata));
-    else
-      callback->Success("null");
+      return JSON::stringify(derivedMetadata);
+
+    return "null";
   }
 
 private:
   Game& game_;
-  std::string pluginName_;
+  const std::string pluginName_;
 };
 }
 
diff --git a/src/gui/query/close_settings_query.h b/src/gui/query/close_settings_query.h
index d897a605..f6738d79 100644
--- a/src/gui/query/close_settings_query.h
+++ b/src/gui/query/close_settings_query.h
@@ -34,11 +34,11 @@ public:
   CloseSettingsQuery(LootState& state, YAML::Node settings) :
     GetInstalledGamesQuery(state), state_(state), settings_(settings) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(trace) << "Settings dialog closed and changes accepted, updating settings object.";
     state_.load(settings_);
 
-    GetInstalledGamesQuery::execute(callback);
+    return GetInstalledGamesQuery::executeLogic();
   }
 
 private:
diff --git a/src/gui/query/copy_content_query.h b/src/gui/query/copy_content_query.h
index be7f95d6..ef8bb16a 100644
--- a/src/gui/query/copy_content_query.h
+++ b/src/gui/query/copy_content_query.h
@@ -34,11 +34,11 @@ class CopyContentQuery : public ClipboardQuery {
 public:
   CopyContentQuery(const YAML::Node& content) : content_(content) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
-    std::string text = "[spoiler][code]" + getContentAsText() + "[/code][/spoiler]";
+  std::string executeLogic() {
+    const std::string text = "[spoiler][code]" + getContentAsText() + "[/code][/spoiler]";
 
     copyToClipboard(text);
-    callback->Success("");
+    return "";
   }
 
 private:
@@ -53,7 +53,7 @@ private:
     return text;
   }
 
-  YAML::Node content_;
+  const YAML::Node content_;
 };
 }
 
diff --git a/src/gui/query/copy_load_order_query.h b/src/gui/query/copy_load_order_query.h
index ab266d39..6ea42af8 100644
--- a/src/gui/query/copy_load_order_query.h
+++ b/src/gui/query/copy_load_order_query.h
@@ -33,7 +33,7 @@ public:
   CopyLoadOrderQuery(LootState& state, const std::vector<std::string>& plugins) :
     state_(state), plugins_(plugins) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     int numberOfIndexDigits = getNumberOfIndexDigits();
 
     size_t activeIndex = 0;
@@ -43,7 +43,7 @@ public:
     }
 
     copyToClipboard(stream.str());
-    callback->Success("");
+    return "";
   }
 
 private:
@@ -67,7 +67,7 @@ private:
   }
 
   LootState& state_;
-  std::vector<std::string> plugins_;
+  const std::vector<std::string> plugins_;
 };
 }
 
diff --git a/src/gui/query/copy_metadata_query.h b/src/gui/query/copy_metadata_query.h
index 2d561034..a8f3c8ee 100644
--- a/src/gui/query/copy_metadata_query.h
+++ b/src/gui/query/copy_metadata_query.h
@@ -35,7 +35,7 @@ public:
   CopyMetadataQuery(LootState& state, const std::string& pluginName) :
     state_(state), pluginName_(pluginName) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(debug) << "Copying metadata for plugin " << pluginName_;
 
     // Get metadata from masterlist and userlist.
@@ -48,6 +48,8 @@ public:
     copyToClipboard(text);
 
     BOOST_LOG_TRIVIAL(info) << "Exported userlist metadata text for \"" << pluginName_ << "\": " << text;
+
+    return "";
   }
 
 private:
diff --git a/src/gui/query/discard_unapplied_changes_query.h b/src/gui/query/discard_unapplied_changes_query.h
index ed9b66b0..94ae7106 100644
--- a/src/gui/query/discard_unapplied_changes_query.h
+++ b/src/gui/query/discard_unapplied_changes_query.h
@@ -33,10 +33,11 @@ class DiscardUnappliedChangesQuery : public Query {
 public:
   DiscardUnappliedChangesQuery(LootState& state) : state_(state) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     while (state_.hasUnappliedChanges())
       state_.decrementUnappliedChangeCounter();
-    callback->Success("");
+
+    return "";
   }
 
 private:
diff --git a/src/gui/query/editor_closed_query.h b/src/gui/query/editor_closed_query.h
index 9ee1bbe8..67610d73 100644
--- a/src/gui/query/editor_closed_query.h
+++ b/src/gui/query/editor_closed_query.h
@@ -35,9 +35,12 @@ public:
     MetadataQuery(state.getCurrentGame(), state.getLanguage().GetCode()),
     state_(state), metadata_(metadata) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     try {
-      callback->Success(applyUserEdits());
+      const std::string json = applyUserEdits();
+      state_.decrementUnappliedChangeCounter();
+
+      return json;
     } catch (Error&) {
       throw;
     } catch (std::exception& e) {
@@ -51,7 +54,6 @@ public:
 
       throw std::runtime_error(error);
     }
-    state_.decrementUnappliedChangeCounter();
   }
 
 private:
diff --git a/src/gui/query/editor_opened_query.h b/src/gui/query/editor_opened_query.h
index dd7da973..d2fd4037 100644
--- a/src/gui/query/editor_opened_query.h
+++ b/src/gui/query/editor_opened_query.h
@@ -33,9 +33,9 @@ class EditorOpenedQuery : public Query {
 public:
   EditorOpenedQuery(LootState& state) : state_(state) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     state_.incrementUnappliedChangeCounter();
-    callback->Success("");
+    return "";
   }
 
 private:
diff --git a/src/gui/query/get_conflicting_plugins_query.h b/src/gui/query/get_conflicting_plugins_query.h
index 945e62fa..526e1997 100644
--- a/src/gui/query/get_conflicting_plugins_query.h
+++ b/src/gui/query/get_conflicting_plugins_query.h
@@ -37,7 +37,7 @@ public:
     game_(state.getCurrentGame()),
     pluginName_(pluginName) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(debug) << "Searching for plugins that conflict with " << pluginName_;
 
     // Checking for FormID overlap will only work if the plugins have been loaded, so check if
@@ -52,9 +52,9 @@ public:
     }
 
     if (node.size() > 0)
-      callback->Success(JSON::stringify(node));
-    else
-      callback->Success("[]");
+      return JSON::stringify(node);
+
+    return "[]";
   }
 
 private:
@@ -76,7 +76,7 @@ private:
   }
 
   Game& game_;
-  std::string pluginName_;
+  const std::string pluginName_;
 };
 }
 
diff --git a/src/gui/query/get_game_data_query.h b/src/gui/query/get_game_data_query.h
index 528fc014..120ea023 100644
--- a/src/gui/query/get_game_data_query.h
+++ b/src/gui/query/get_game_data_query.h
@@ -41,7 +41,7 @@ public:
     state_(state),
     frame_(frame) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     sendProgressUpdate(frame_, boost::locale::translate("Parsing, merging and evaluating metadata..."));
 
     // First clear CRC and condition caches, otherwise they could lead to incorrect evaluations.
@@ -64,7 +64,7 @@ public:
       } catch (...) {}
     }
 
-    callback->Success(generateJsonResponse(installed));
+    return generateJsonResponse(installed);
   }
 
 private:
diff --git a/src/gui/query/get_game_types_query.h b/src/gui/query/get_game_types_query.h
index 37b2642a..1e466047 100644
--- a/src/gui/query/get_game_types_query.h
+++ b/src/gui/query/get_game_types_query.h
@@ -32,9 +32,9 @@ along with LOOT.  If not, see
 namespace loot {
 class GetGameTypesQuery : public Query {
 public:
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(info) << "Getting LOOT's supported languages.";
-    callback->Success(getGameTypesAsJson());
+    return getGameTypesAsJson();
   }
 
 private:
diff --git a/src/gui/query/get_init_errors_query.h b/src/gui/query/get_init_errors_query.h
index e79c20e8..d2d36b75 100644
--- a/src/gui/query/get_init_errors_query.h
+++ b/src/gui/query/get_init_errors_query.h
@@ -34,12 +34,12 @@ class GetInitErrorsQuery : public Query {
 public:
   GetInitErrorsQuery(LootState& state) : state_(state) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     YAML::Node node(state_.getInitErrors());
     if (node.size() > 0)
-      callback->Success(JSON::stringify(node));
-    else
-      callback->Success("null");
+      return JSON::stringify(node);
+
+    return "null";
   }
 
 private:
diff --git a/src/gui/query/get_installed_games_query.h b/src/gui/query/get_installed_games_query.h
index 67085fe1..bb83084d 100644
--- a/src/gui/query/get_installed_games_query.h
+++ b/src/gui/query/get_installed_games_query.h
@@ -34,9 +34,9 @@ class GetInstalledGamesQuery : public Query {
 public:
   GetInstalledGamesQuery(LootState& state) : state_(state) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(info) << "Getting LOOT's detected games.";
-    callback->Success(getInstalledGamesAsJson());
+    return getInstalledGamesAsJson();
   }
 
 private:
diff --git a/src/gui/query/get_languages_query.h b/src/gui/query/get_languages_query.h
index 5acb7f65..dc259364 100644
--- a/src/gui/query/get_languages_query.h
+++ b/src/gui/query/get_languages_query.h
@@ -32,9 +32,9 @@ along with LOOT.  If not, see
 namespace loot {
 class GetLanguagesQuery : public Query {
 public:
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(info) << "Getting LOOT's supported languages.";
-    callback->Success(getLanguagesAsJson());
+    return getLanguagesAsJson();
   }
 
 private:
diff --git a/src/gui/query/get_settings_query.h b/src/gui/query/get_settings_query.h
index e5c0e068..0aac9fe7 100644
--- a/src/gui/query/get_settings_query.h
+++ b/src/gui/query/get_settings_query.h
@@ -34,13 +34,13 @@ class GetSettingsQuery : public Query {
 public:
   GetSettingsQuery(LootSettings& settings) : settings_(settings) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(info) << "Getting LOOT settings.";
-    callback->Success(JSON::stringify(settings_.toYaml()));
+    return JSON::stringify(settings_.toYaml());
   }
 
 private:
-  LootSettings& settings_;
+  const LootSettings& settings_;
 };
 }
 
diff --git a/src/gui/query/get_version_query.h b/src/gui/query/get_version_query.h
index 592806a3..a477b07c 100644
--- a/src/gui/query/get_version_query.h
+++ b/src/gui/query/get_version_query.h
@@ -31,9 +31,9 @@ along with LOOT.  If not, see
 namespace loot {
 class GetVersionQuery : public Query {
 public:
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(info) << "Getting LOOT version.";
-    callback->Success("\"" + LootVersion::string() + "." + LootVersion::revision + "\"");
+    return "\"" + LootVersion::string() + "." + LootVersion::revision + "\"";
   }
 };
 }
diff --git a/src/gui/query/metadata_query.h b/src/gui/query/metadata_query.h
index 1476ee8c..07175510 100644
--- a/src/gui/query/metadata_query.h
+++ b/src/gui/query/metadata_query.h
@@ -148,7 +148,7 @@ private:
   }
 
   Game& game_;
-  LanguageCode language_;
+  const LanguageCode language_;
 };
 }
 
diff --git a/src/gui/query/open_log_location_query.h b/src/gui/query/open_log_location_query.h
index bb2d9575..978996ff 100644
--- a/src/gui/query/open_log_location_query.h
+++ b/src/gui/query/open_log_location_query.h
@@ -32,11 +32,11 @@ along with LOOT.  If not, see
 namespace loot {
 class OpenLogLocationQuery : public Query {
 public:
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(info) << "Opening LOOT local appdata folder.";
     OpenInDefaultApplication(LootPaths::getLogPath().parent_path());
 
-    callback->Success("");
+    return "";
   }
 };
 }
diff --git a/src/gui/query/open_readme_query.h b/src/gui/query/open_readme_query.h
index 2d247afd..542e6cd0 100644
--- a/src/gui/query/open_readme_query.h
+++ b/src/gui/query/open_readme_query.h
@@ -32,11 +32,11 @@ along with LOOT.  If not, see
 namespace loot {
 class OpenReadmeQuery : public Query {
 public:
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(info) << "Opening LOOT readme.";
     OpenInDefaultApplication(LootPaths::getReadmePath());
 
-    callback->Success("");
+    return "";
   }
 };
 }
diff --git a/src/gui/query/query.h b/src/gui/query/query.h
index a9ebd72f..b10861bd 100644
--- a/src/gui/query/query.h
+++ b/src/gui/query/query.h
@@ -28,12 +28,26 @@ along with LOOT.  If not, see
 #include <boost/log/trivial.hpp>
 #include <include/wrapper/cef_message_router.h>
 
+#include "loot/error.h"
+
 namespace loot {
 class Query : public CefBase {
 public:
-  virtual void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) = 0;
+  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+    try {
+      callback->Success(executeLogic());
+    } catch (Error &e) {
+      BOOST_LOG_TRIVIAL(error) << e.what();
+      callback->Failure(e.codeAsUnsignedInt(), e.what());
+    } catch (std::exception &e) {
+      BOOST_LOG_TRIVIAL(error) << e.what();
+      callback->Failure(-1, e.what());
+    }
+  }
 
 protected:
+  virtual std::string executeLogic() = 0;
+
   void sendProgressUpdate(CefRefPtr<CefFrame> frame, const std::string& message) {
     BOOST_LOG_TRIVIAL(trace) << "Sending progress update: " << message;
     frame->ExecuteJavaScript("loot.Dialog.showProgress('" + message + "');", frame->GetURL(), 0);
diff --git a/src/gui/query/redate_plugins_query.h b/src/gui/query/redate_plugins_query.h
index 9c11bbd0..5afe886f 100644
--- a/src/gui/query/redate_plugins_query.h
+++ b/src/gui/query/redate_plugins_query.h
@@ -33,9 +33,9 @@ class RedatePluginsQuery : public Query {
 public:
   RedatePluginsQuery(LootState& state) : state_(state) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     state_.getCurrentGame().RedatePlugins();
-    callback->Success("");
+    return "";
   }
 
 private:
diff --git a/src/gui/query/save_filter_state_query.h b/src/gui/query/save_filter_state_query.h
index 84737e15..fb2f8b20 100644
--- a/src/gui/query/save_filter_state_query.h
+++ b/src/gui/query/save_filter_state_query.h
@@ -38,10 +38,10 @@ public:
                        bool enabled) :
     state_(state), filterId_(filterId), enabled_(enabled) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(trace) << "Saving filter states.";
     state_.storeFilterState(filterId_, enabled_);
-    callback->Success("");
+    return "";
   }
 
 private:
diff --git a/src/gui/query/sort_plugins_query.h b/src/gui/query/sort_plugins_query.h
index 8ecdb5d0..d3c17f56 100644
--- a/src/gui/query/sort_plugins_query.h
+++ b/src/gui/query/sort_plugins_query.h
@@ -39,7 +39,7 @@ public:
     state_(state),
     frame_(frame) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(info) << "Beginning sorting operation.";
 
     // Always reload all the plugins.
@@ -52,11 +52,13 @@ public:
     if ((state_.getCurrentGame().Type() == GameType::tes5 || state_.getCurrentGame().Type() == GameType::fo4))
       applyUnchangedLoadOrder(plugins);
 
-    callback->Success(generateJsonResponse(plugins));
+    std::string json = generateJsonResponse(plugins);
 
     // plugins will be empty if there was a sorting error.
     if (!plugins.empty())
       state_.incrementUnappliedChangeCounter();
+
+    return json;
   }
 
 private:
@@ -78,7 +80,7 @@ private:
   }
 
   void applyUnchangedLoadOrder(const std::vector<Plugin>& plugins) {
-    if (!equal(begin(plugins), end(plugins), begin(state_.getCurrentGame().GetLoadOrder())))
+    if (plugins.empty() || !equal(begin(plugins), end(plugins), begin(state_.getCurrentGame().GetLoadOrder())))
       return;
 
     // Load order has not been changed, set it without asking for user input
diff --git a/src/gui/query/update_masterlist_query.h b/src/gui/query/update_masterlist_query.h
index 19bfbf28..6d786a27 100644
--- a/src/gui/query/update_masterlist_query.h
+++ b/src/gui/query/update_masterlist_query.h
@@ -36,16 +36,14 @@ public:
     MetadataQuery(state.getCurrentGame(), state.getLanguage().GetCode()),
     game_(state.getCurrentGame()) {}
 
-  void execute(CefRefPtr<CefMessageRouterBrowserSide::Callback> callback) {
+  std::string executeLogic() {
     BOOST_LOG_TRIVIAL(debug) << "Updating and parsing masterlist.";
 
-    if (!updateMasterlist()) {
-      callback->Success("null");
-      return;
-    }
+    if (!updateMasterlist())
+      return "null";
 
     // Now regenerate the JS-side masterlist data if the masterlist was changed.
-    callback->Success(generateJsonResponse());
+    return generateJsonResponse();
   }
 
 private:
diff --git a/src/gui/query_handler.cpp b/src/gui/query_handler.cpp
index 94a5ec3d..bee78c5c 100644
--- a/src/gui/query_handler.cpp
+++ b/src/gui/query_handler.cpp
@@ -111,15 +111,7 @@ bool QueryHandler::OnQuery(CefRefPtr<CefBrowser> browser,
   if (!query)
     return false;
 
-  try {
-    CefPostTask(TID_FILE, base::Bind(&Query::execute, query, callback));
-  } catch (Error &e) {
-    BOOST_LOG_TRIVIAL(error) << e.what();
-    callback->Failure(e.codeAsUnsignedInt(), e.what());
-  } catch (exception &e) {
-    BOOST_LOG_TRIVIAL(error) << e.what();
-    callback->Failure(-1, e.what());
-  }
+  CefPostTask(TID_FILE, base::Bind(&Query::execute, query, callback));
 
   return true;
 }