diff --git a/library/file b/library/file
index 892696dd15..2575c57c39 100755
--- a/library/file
+++ b/library/file
@@ -184,8 +184,14 @@ def user_and_group(filename):
     st = os.stat(filename)
     uid = st.st_uid
     gid = st.st_gid
-    user = pwd.getpwuid(uid)[0]
-    group = grp.getgrgid(gid)[0]
+    try:
+        user = pwd.getpwuid(uid)[0]
+    except KeyError:
+        user = str(uid)
+    try:
+        group = grp.getgrgid(gid)[0]
+    except KeyError:
+        group = str(gid)
     return (user, group)
 
 def set_context_if_different(path, context, changed):