diff --git a/code/ryzom/tools/client/ryzom_installer/src/configfile.cpp b/code/ryzom/tools/client/ryzom_installer/src/configfile.cpp
index 06c525053..1ec7364cc 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/configfile.cpp
+++ b/code/ryzom/tools/client/ryzom_installer/src/configfile.cpp
@@ -593,6 +593,11 @@ bool CConfigFile::areRyzomDataInstalledIn(const QString &directory) const
 
 	QDir dir(directory);
 
+#ifdef Q_OS_MAC
+	// under OS X, data are in Ryzom.app/Contents/Resources
+	if (!dir.cd("Ryzom.app") || !dir.cd("Contents") || !dir.cd("Resources")) return false;
+#endif
+
 	// directory doesn't exist
 	if (!dir.exists()) return false;
 
@@ -643,6 +648,11 @@ bool CConfigFile::isRyzomClientInstalledIn(const QString &directory) const
 	{
 		// client 3.0+
 
+#ifdef Q_OS_MAC
+		// under OS X, client_default.cfg is in Ryzom.app/Contents/Resources
+		if (!dir.cd("Ryzom.app") || !dir.cd("Contents") || !dir.cd("Resources")) return false;
+#endif
+
 		// client_default.cfg doesn't exist
 		if (!dir.exists("client_default.cfg")) return false;
 
diff --git a/code/ryzom/tools/client/ryzom_installer/src/operationdialog.cpp b/code/ryzom/tools/client/ryzom_installer/src/operationdialog.cpp
index 9c84f46cf..4213bec73 100644
--- a/code/ryzom/tools/client/ryzom_installer/src/operationdialog.cpp
+++ b/code/ryzom/tools/client/ryzom_installer/src/operationdialog.cpp
@@ -547,9 +547,16 @@ void COperationDialog::extractDownloadedData()
 
 	m_currentOperation = tr("Extracting data required by server %1...").arg(server.name);
 
+	QString dest = server.getDirectory();
+
+#ifdef Q_OS_MAC
+	// under OS X, data should be uncompressed in Ryzom.app/Contents/Resources
+	dest += "/Ryzom.app/Contents/Resources";
+#endif
+
 	CFilesExtractor extractor(this);
 	extractor.setSourceFile(config->getInstallationDirectory() + "/" + server.dataDownloadFilename);
-	extractor.setDestinationDirectory(server.getDirectory());
+	extractor.setDestinationDirectory(dest);
 
 	if (extractor.exec())
 	{