diff --git a/sources/main.cpp b/sources/main.cpp
index b0f32a237..efa0b46b4 100644
--- a/sources/main.cpp
+++ b/sources/main.cpp
@@ -91,10 +91,6 @@ int main(int argc, char **argv)
 	// export environment-variable "QT_HASH_SEED" with value "0" to
 	// disable radomisation for hashes in order to obtain "clean" XML-diffs:
 	qputenv("QT_HASH_SEED", "0");
-	//Some setup, notably to use with QSetting.
-	QCoreApplication::setOrganizationName("QElectroTech");
-	QCoreApplication::setOrganizationDomain("qelectrotech.org");
-	QCoreApplication::setApplicationName("QElectroTech");
 
 	// Refuse invalid data when building QDom documents instead of
 	// serializing malformed XML (CVE-2026-15037). This is the default
@@ -173,6 +169,65 @@ QGuiApplication::setHighDpiScaleFactorRoundingPolicy(QetSettings::hdpiScaleFacto
 		return 0;
 	}
 
+/******************************************************************************/
+#ifdef Q_OS_WINDOWS
+	// install-version of QET normally resides in "C:\Program Files\QElectroTech"
+	// "normal" users are usually not allowed to create files or directories
+	// there, so if we are not allowed to write there, it is most likely that
+	// QET is installed. ReadyToUse-versions should reside in other directory
+	// like C:\Tools\QElectroTech, where it is allowed to create sub-dirs.
+	// Check if up-dir of QET-binary is writable for us:
+	const QFileInfo fi(QDir::cleanPath(QCoreApplication::applicationDirPath() % "/../"));
+	const bool pathIsWritable(fi.isDir() && fi.isWritable());
+	bool useRegistry(false);
+	// set name of path for configuration
+	QString confPath = QDir::cleanPath(QCoreApplication::applicationDirPath() % "/../conf/");
+	// check registry, if QET is already using it
+	QSettings regCheck("HKEY_CURRENT_USER\\Software\\" % QCoreApplication::organizationName(),
+						QSettings::NativeFormat);
+	if (regCheck.childGroups().contains(QCoreApplication::applicationName())) {
+		// registry-key already exists? --> use registry!
+		useRegistry = true;
+	} else if (QDir(confPath).exists() && (pathIsWritable == true)) {
+		// config-dir already exists? --> use it!
+		useRegistry = false;
+	} else if (pathIsWritable == true) {
+		// only ask user what to do, if we are allowed to create conf-dir
+		QMessageBox::StandardButton configReply;
+		configReply = QMessageBox::question(NULL,
+							QObject::tr("QElectroTech-Config", "title of QMessageBox: Choose location of configuration"),
+							QObject::tr("Save the configuration to registry?\n\nYes -> use Windows-Registry (default)\nNo -> use INI-file in conf-dir"),
+							QMessageBox::Yes | QMessageBox::No,
+							QMessageBox::Yes);
+		if (configReply == QMessageBox::Yes) {
+			// Config in Registry:
+			useRegistry = true;
+		} else {
+			// Config in User-Dir:
+			useRegistry = false;
+		}
+	} else {
+		// fallback
+		useRegistry = true;
+	}
+#endif
+	//Some setup, notably to use with QSetting ... with every system!
+	QCoreApplication::setOrganizationName("QElectroTech");
+	QCoreApplication::setOrganizationDomain("qelectrotech.org");
+	QCoreApplication::setApplicationName("QElectroTech");
+#ifdef Q_OS_WINDOWS
+	// set chosen way of saving config for win:
+	if (useRegistry == true) {
+		QSettings::setDefaultFormat(QSettings::NativeFormat);
+		qInfo() << "using Windows-Registry to save configuration";
+	} else {
+		QSettings::setPath(QSettings::IniFormat, QSettings::UserScope, confPath);
+		QSettings::setDefaultFormat(QSettings::IniFormat);
+		qInfo() << "using directory" << confPath << "to save configuration";
+	}
+#endif
+/******************************************************************************/
+
 	QETApp qetapp;
 	QETApp::instance()->installEventFilter(&qetapp);
 #ifdef Q_OS_MACOS