diff --git a/dom0/qvm-core/qubesutils.py b/dom0/qvm-core/qubesutils.py
index 46a5f69a..81d5a222 100644
--- a/dom0/qvm-core/qubesutils.py
+++ b/dom0/qvm-core/qubesutils.py
@@ -341,7 +341,7 @@ def block_attach(vm, backend_vm, device, frontend=None, mode="w", auto_detach=Fa
                 return
             elif int(be_state) > 4:
                 # Error
-                error = xs.read('/local/domain/%d/error/backend/vbd/%d/%d/error' % (backend_vm.xid, vm.xid, block_name_to_devid(frontend)))
+                error = xs.read('', '/local/domain/%d/error/backend/vbd/%d/%d/error' % (backend_vm.xid, vm.xid, block_name_to_devid(frontend)))
                 if error is None:
                     raise QubesException("Error while connecting block device: " + error)
                 else: