diff -Nur -Xsnap/diff_ignore snap/common/improvement.c snap-obsol/common/improvement.c
--- snap/common/improvement.c	2003-04-04 15:40:27.000000000 -0600
+++ snap-obsol/common/improvement.c	2003-07-26 14:40:12.000000000 -0500
@@ -623,6 +623,10 @@
   players_iterate(pplayer) {
     city_list_iterate(pplayer->cities, pcity) {
       built_impr_iterate(pcity, i) {
+        if (pcity->improvements[i] == I_OBSOLETE) {
+          continue;
+        }
+
         if (improvement_obsolete(pplayer, i)) {
           freelog(LOG_DEBUG,"%s in %s is obsolete",
                   improvement_types[i].name, pcity->name);