$OpenBSD: patch-src_lib-index_mail-index-sync-update_c,v 1.1 2011/01/04 13:59:17 pea Exp $
--- src/lib-index/mail-index-sync-update.c.orig	Sun Dec  5 18:18:06 2010
+++ src/lib-index/mail-index-sync-update.c	Sun Dec  5 18:18:45 2010
@@ -528,8 +528,15 @@ int mail_index_sync_record(struct mail_index_sync_map_
 			break;
 		}
 		end = CONST_PTR_OFFSET(data, hdr->size);
-		for (; rec != end; rec++)
+		for (; rec != end; rec++) {
+			if (rec->uid == 0) {
+				mail_index_sync_set_corrupted(ctx,
+					"Expunge-guid for invalid uid=%u",
+					rec->uid);
+				break;
+			}
 			sync_expunge(ctx, rec->uid, rec->uid);
+		}
 		break;
 	}
 	case MAIL_TRANSACTION_FLAG_UPDATE: {
