diff --git a/qtest/dune b/qtest/dune
index e3b5e712..5775f212 100644
--- a/qtest/dune
+++ b/qtest/dune
@@ -19,7 +19,7 @@
 
 (alias
   (name    runtest)
-  (locks ctest)
+  (locks /ctest)
   (package containers)
   (action  (run ./run_qtest.exe)))
 
@@ -39,7 +39,7 @@
 (alias
   (name    runtest)
   (package containers-data)
-  (locks ctest)
+  (locks /ctest)
   (action  (run ./run_qtest_data.exe)))
 
 (rule
@@ -57,6 +57,6 @@
 
 (alias
   (name    runtest)
-  (locks ctest)
+  (locks /ctest)
   (package containers-thread)
   (action  (run ./run_qtest_thread.exe)))
diff --git a/src/core/tests/dune b/src/core/tests/dune
index ef6300eb..bca775fc 100644
--- a/src/core/tests/dune
+++ b/src/core/tests/dune
@@ -20,13 +20,13 @@
 
 (alias
   (name runtest)
-  (locks ctest)
+  (locks /ctest)
   (package containers)
   (action (run ./test_random.exe)))
 
 ; what matters is that it compiles
 (alias
   (name runtest)
-  (locks ctest)
+  (locks /ctest)
   (package containers)
   (action  (run ./check_labelled_mods.exe)))