diff --git a/mdetach.c b/mdetach.c
index 956e7ea..7b13342 100644
--- a/mdetach.c
+++ b/mdetach.c
@@ -17,6 +17,10 @@ int mdetach(Entry *e, void *p1, void *p2, void *p3, void *p4, void *p5)
     IncBusy();
     TCPIPCloseTCP(e->ipid);
     
+    // hmmm this is in the close() call, so the 
+    // fd won't be valid afterwards....
+    e->select_rd_pid = 0xffff;
+    e->select_wr_pid = 0xffff;
     e->command = kCommandDisconnectAndLogout;
     e->cookie = 0;
     e->timeout = timeout;