frontend: Localize startup failures with typed errors

frontend/OBSApp.cpp

@@ -22,6 +22,7 @@
 #include <plugin-manager/PluginManager.hpp>
 #include <utility/CrashHandler.hpp>
 #include <utility/OBSEventFilter.hpp>
+#include <utility/OBSInitException.hpp>
 #include <utility/OBSProxyStyle.hpp>
 #if defined(_WIN32) || defined(ENABLE_SPARKLE_UPDATER)
 #include <utility/models/branches.hpp>
@@ -1081,16 +1082,16 @@ void OBSApp::AppInit()
 	QAccessible::installFactory(alignmentSelectorFactory);
 
 	if (!MakeUserDirs()) {
-		throw "Failed to create required user directories";
+		throw OBSInitException(OBSInitErrorCode::UserDirs, "Failed to create required user directories");
 	}
 	if (!InitGlobalConfig()) {
-		throw "Failed to initialize global config";
+		throw OBSInitException(OBSInitErrorCode::GlobalConfig, "Failed to initialize global config");
 	}
 	if (!InitLocale()) {
-		throw "Failed to load locale";
+		throw OBSInitException(OBSInitErrorCode::Locale, "Failed to load locale");
 	}
 	if (!InitTheme()) {
-		throw "Failed to load theme";
+		throw OBSInitException(OBSInitErrorCode::Theme, "Failed to load theme");
 	}
 
 	config_set_default_string(userConfig, "Basic", "Profile", Str("Untitled"));
@@ -1132,7 +1133,7 @@ void OBSApp::AppInit()
 	move_basic_to_scene_collections();
 
 	if (!MakeUserProfileDirs()) {
-		throw "Failed to create profile directories";
+		throw OBSInitException(OBSInitErrorCode::ProfileDirs, "Failed to create profile directories");
 	}
 }
 
@@ -1687,12 +1688,12 @@ vector<pair<string, string>> GetLocaleNames()
 {
 	string path;
 	if (!GetDataFilePath("locale.ini", path)) {
-		throw "Could not find locale.ini path";
+		throw OBSInitException(OBSInitErrorCode::LocaleIniPath, "Could not find locale.ini path");
 	}
 
 	ConfigFile ini;
 	if (ini.Open(path.c_str(), CONFIG_OPEN_EXISTING) != 0) {
-		throw "Could not open locale.ini";
+		throw OBSInitException(OBSInitErrorCode::LocaleIniOpen, "Could not open locale.ini");
 	}
 
 	size_t sections = config_num_sections(ini);

frontend/cmake/ui-utility.cmake

@@ -25,6 +25,8 @@ target_sources(
     utility/MissingFilesPathItemDelegate.hpp
     utility/MultitrackVideoError.cpp
     utility/MultitrackVideoError.hpp
+    utility/OBSInitException.cpp
+    utility/OBSInitException.hpp
     utility/MultitrackVideoOutput.cpp
     utility/MultitrackVideoOutput.hpp
     utility/NativeEventFilter.hpp

frontend/data/locale/en-US.ini

@@ -5,6 +5,16 @@
 # Language of this file
 Language="English"
 
+# Startup / initialization errors
+Init.Error.UserDirs="Failed to create required user directories."
+Init.Error.GlobalConfig="Failed to initialize the global configuration."
+Init.Error.Locale="Failed to load the application language files."
+Init.Error.Theme="Failed to load the application theme."
+Init.Error.ProfileDirs="Failed to create profile directories."
+Init.Error.LocaleIniPath="Could not find the locale.ini path."
+Init.Error.LocaleIniOpen="Could not open locale.ini."
+Init.Error.Unknown="OBS Studio failed to start."
+
 # commonly shared locale
 OK="OK"
 Apply="Apply"

frontend/obs-main.cpp

@@ -22,6 +22,7 @@
 #include <dialogs/OBSPermissions.hpp>
 #endif
 #include <utility/BaseLexer.hpp>
+#include <utility/OBSInitException.hpp>
 #include <utility/OBSTranslator.hpp>
 #include <utility/platform.hpp>
 
@@ -690,6 +691,9 @@ static int run_program(fstream &logFile, int argc, char *argv[])
 
 		ret = program.exec();
 
+	} catch (const OBSInitException &error) {
+		blog(LOG_ERROR, "OBS init failed (%s): %s", OBSInitException::codeName(error.code()), error.what());
+		OBSErrorBox(nullptr, "%s", QT_TO_UTF8(error.localizedMessage()));
 	} catch (const char *error) {
 		blog(LOG_ERROR, "%s", error);
 		OBSErrorBox(nullptr, "%s", error);

frontend/utility/OBSInitException.cpp

@@ -0,0 +1,42 @@
+/******************************************************************************
+    Copyright (C) 2026 by Ray Winkelman <rwinkelman@users.noreply.github.com>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+#include "OBSInitException.hpp"
+
+#include "OBSApp.hpp"
+
+QString OBSInitException::localizedMessage() const
+{
+	switch (code_) {
+	case OBSInitErrorCode::UserDirs:
+		return QTStr("Init.Error.UserDirs");
+	case OBSInitErrorCode::GlobalConfig:
+		return QTStr("Init.Error.GlobalConfig");
+	case OBSInitErrorCode::Locale:
+		return QTStr("Init.Error.Locale");
+	case OBSInitErrorCode::Theme:
+		return QTStr("Init.Error.Theme");
+	case OBSInitErrorCode::ProfileDirs:
+		return QTStr("Init.Error.ProfileDirs");
+	case OBSInitErrorCode::LocaleIniPath:
+		return QTStr("Init.Error.LocaleIniPath");
+	case OBSInitErrorCode::LocaleIniOpen:
+		return QTStr("Init.Error.LocaleIniOpen");
+	}
+
+	return QTStr("Init.Error.Unknown");
+}

frontend/utility/OBSInitException.hpp

@@ -0,0 +1,74 @@
+/******************************************************************************
+    Copyright (C) 2026 by Ray Winkelman <rwinkelman@users.noreply.github.com>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+******************************************************************************/
+
+#pragma once
+
+#include <QString>
+
+#include <exception>
+#include <string>
+#include <utility>
+
+enum class OBSInitErrorCode {
+	UserDirs,
+	GlobalConfig,
+	Locale,
+	Theme,
+	ProfileDirs,
+	LocaleIniPath,
+	LocaleIniOpen,
+};
+
+class OBSInitException : public std::exception {
+public:
+	explicit OBSInitException(OBSInitErrorCode code, std::string detail = {})
+		: code_(code),
+		  detail_(std::move(detail))
+	{
+	}
+
+	OBSInitErrorCode code() const { return code_; }
+
+	const char *what() const noexcept override { return detail_.empty() ? codeName(code_) : detail_.c_str(); }
+
+	QString localizedMessage() const;
+
+	static const char *codeName(OBSInitErrorCode code)
+	{
+		switch (code) {
+		case OBSInitErrorCode::UserDirs:
+			return "UserDirs";
+		case OBSInitErrorCode::GlobalConfig:
+			return "GlobalConfig";
+		case OBSInitErrorCode::Locale:
+			return "Locale";
+		case OBSInitErrorCode::Theme:
+			return "Theme";
+		case OBSInitErrorCode::ProfileDirs:
+			return "ProfileDirs";
+		case OBSInitErrorCode::LocaleIniPath:
+			return "LocaleIniPath";
+		case OBSInitErrorCode::LocaleIniOpen:
+			return "LocaleIniOpen";
+		}
+		return "Unknown";
+	}
+
+private:
+	OBSInitErrorCode code_;
+	std::string detail_;
+};