diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 1369977c1..65c7328e7 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,8 @@
+2014-03-12  Corinna Vinschen  <corinna@vinschen.de>
+
+	* uinfo.cc (pwdgrp::fetch_account_from_windows): Avoid crash on
+	non-domain member machines if an unknown SID comes in.
+
 2014-03-12  Corinna Vinschen  <corinna@vinschen.de>
 
 	* include/cygwin/socket.h (IPV6_JOIN_GROUP): Revert.
diff --git a/winsup/cygwin/uinfo.cc b/winsup/cygwin/uinfo.cc
index d1304ebff..10d335644 100644
--- a/winsup/cygwin/uinfo.cc
+++ b/winsup/cygwin/uinfo.cc
@@ -1752,7 +1752,8 @@ pwdgrp::fetch_account_from_windows (fetch_user_arg_t &arg, cyg_ldap *pldap)
     }
   else
     {
-      if (sid_id_auth (sid) == 5 /* SECURITY_NT_AUTHORITY */
+      if (cygheap->dom.member_machine ()
+	  && sid_id_auth (sid) == 5 /* SECURITY_NT_AUTHORITY */
 	  && sid_sub_auth (sid, 0) == SECURITY_NT_NON_UNIQUE)
 	{
 	  /* Check if we know the domain.  If so, create a passwd/group