diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index 2d2762ea4..ab65505b1 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -126,7 +126,7 @@ public:
 
     Setting<std::string> gcSocketPath {
         this,
-        getEnv("NIX_GC_SOCKET_PATH").value_or("auto"),
+        "auto",
         "gc-socket-path",
         "Path to the socket used to communicate with an external GC."
     };
diff --git a/tests/gc-external-daemon/common.sh b/tests/gc-external-daemon/common.sh
index 01e75e1bd..746de5c1a 100644
--- a/tests/gc-external-daemon/common.sh
+++ b/tests/gc-external-daemon/common.sh
@@ -1,5 +1,6 @@
 source ../common.sh
 
 enableFeatures "external-gc-daemon"
+echo "gc-socket-path = $NIX_GC_SOCKET_PATH" >> "$NIX_CONF_DIR"/nix.cong
 
 startGcDaemon