diff --git a/xs/src/libslic3r/utils.cpp b/xs/src/libslic3r/utils.cpp
index 34b9eaa9f..14736468a 100644
--- a/xs/src/libslic3r/utils.cpp
+++ b/xs/src/libslic3r/utils.cpp
@@ -119,7 +119,7 @@ static std::string g_data_dir;
 
 void set_data_dir(const std::string &dir)
 {
-    g_data_dir = dir;
+    g_data_dir = dir + "-alpha";    // FIXME: Resolve backcompat problems
 }
 
 const std::string& data_dir()