diff --git a/mercurial/narrowspec.py b/mercurial/narrowspec.py
--- a/mercurial/narrowspec.py
+++ b/mercurial/narrowspec.py
@@ -190,12 +190,14 @@
 def restorewcbackup(repo, backupname):
     if repository.NARROW_REQUIREMENT not in repo.requirements:
         return
-    util.rename(repo.vfs.join(backupname), repo.vfs.join(DIRSTATE_FILENAME))
+    # It may not exist in old repos
+    if repo.vfs.exists(backupname):
+        util.rename(repo.vfs.join(backupname), repo.vfs.join(DIRSTATE_FILENAME))
 
 def clearwcbackup(repo, backupname):
     if repository.NARROW_REQUIREMENT not in repo.requirements:
         return
-    repo.vfs.unlink(backupname)
+    repo.vfs.tryunlink(backupname)
 
 def restrictpatterns(req_includes, req_excludes, repo_includes, repo_excludes):
     r""" Restricts the patterns according to repo settings,
diff --git a/tests/test-narrow-share.t b/tests/test-narrow-share.t
--- a/tests/test-narrow-share.t
+++ b/tests/test-narrow-share.t
@@ -166,7 +166,7 @@
   R d7/f
 Make it look like a repo from before narrow+share was supported
   $ rm .hg/narrowspec.dirstate
-  $ hg st
+  $ hg ci -Am test
   abort: working copy's narrowspec is stale
   (run 'hg tracked --update-working-copy')
   [255]