diff --git a/drivers/FileSR.py b/drivers/FileSR.py
index 848b5d951..3fd15ad12 100755
--- a/drivers/FileSR.py
+++ b/drivers/FileSR.py
@@ -668,6 +668,7 @@ def compose(self, sr_uuid, vdi1, vdi2):
         assert(util.pathexists(parent_path))
         vhdutil.setParent(self.path, parent_path, False)
         vhdutil.setHidden(parent_path)
+        self.sr.session.xenapi.VDI.set_managed(self.sr.srcmd.params['args'][0], False)
         util.pread2([vhdutil.VHD_UTIL, "modify", "-p", parent_path,
             "-n", self.path])
         # Tell tapdisk the chain has changed
diff --git a/drivers/LVHDSR.py b/drivers/LVHDSR.py
index 83de1c4c5..6d219cd54 100755
--- a/drivers/LVHDSR.py
+++ b/drivers/LVHDSR.py
@@ -1572,6 +1572,7 @@ def compose(self, sr_uuid, vdi1, vdi2):
 
         vhdutil.setParent(self.path, parent_path, False)
         vhdutil.setHidden(parent_path)
+        self.sr.session.xenapi.VDI.set_managed(self.sr.srcmd.params['args'][0], False)
 
         if not blktap2.VDI.tap_refresh(self.session, self.sr.uuid, self.uuid,
                 True):