diff --git a/mercurial/dirstateguard.py b/mercurial/dirstateguard.py
--- a/mercurial/dirstateguard.py
+++ b/mercurial/dirstateguard.py
@@ -7,6 +7,7 @@
 
 from __future__ import absolute_import
 
+import os
 from .i18n import _
 
 from . import (
@@ -34,11 +35,12 @@
         self._repo = repo
         self._active = False
         self._closed = False
-        self._backupname = b'dirstate.backup.%s.%d' % (name, id(self))
-        self._narrowspecbackupname = b'narrowspec.backup.%s.%d' % (
-            name,
-            id(self),
-        )
+        def getname(prefix):
+            fd, fname = repo.vfs.mkstemp(prefix=prefix)
+            os.close(fd)
+            return fname
+        self._backupname = getname(b'dirstate.backup.%s.' % name)
+        self._narrowspecbackupname = getname(b'narrowspec.backup.%s.' % name)
         repo.dirstate.savebackup(repo.currenttransaction(), self._backupname)
         narrowspec.savewcbackup(repo, self._narrowspecbackupname)
         self._active = True