diff --git a/myisam/mi_extra.c b/myisam/mi_extra.c
index 5eb5010ad8c..71e65153eac 100644
--- a/myisam/mi_extra.c
+++ b/myisam/mi_extra.c
@@ -278,7 +278,7 @@ int mi_extra(MI_INFO *info, enum ha_extra_function function, void *extra_arg)
   case HA_EXTRA_PREPARE_FOR_DELETE:
     pthread_mutex_lock(&THR_LOCK_myisam);
     share->last_version= 0L;			/* Impossible version */
-#ifdef __WIN__
+#ifdef __WIN__REMOVE_OBSOLETE_WORKAROUND
     /* Close the isam and data files as Win32 can't drop an open table */
     pthread_mutex_lock(&share->intern_lock);
     if (flush_key_blocks(share->key_cache, share->kfile,
diff --git a/mysql-test/r/alter_table.result b/mysql-test/r/alter_table.result
index 4eace9ac628..f24a1788404 100644
--- a/mysql-test/r/alter_table.result
+++ b/mysql-test/r/alter_table.result
@@ -903,3 +903,15 @@ f1	f2	f21	f4	f41
 1	2000-01-01 00:00:00	2000-01-01	2002-02-02 00:00:00	2002-02-02
 drop table t1;
 set sql_mode= @orig_sql_mode;
+create table t1 (c char(10) default "Two");
+lock table t1 write;
+insert into t1 values ();
+alter table t1 modify c char(10) default "Three";
+unlock tables;
+select * from t1;
+c
+Two
+check table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+drop table t1;
diff --git a/mysql-test/t/alter_table.test b/mysql-test/t/alter_table.test
index 3ced1087757..bcca122f9f8 100644
--- a/mysql-test/t/alter_table.test
+++ b/mysql-test/t/alter_table.test
@@ -684,3 +684,15 @@ alter table t1 add column f4 datetime not null default '2002-02-02',
 select * from t1;
 drop table t1;
 set sql_mode= @orig_sql_mode;
+
+#
+# BUG#29957 - alter_table.test fails
+#
+create table t1 (c char(10) default "Two");
+lock table t1 write;
+insert into t1 values ();
+alter table t1 modify c char(10) default "Three";
+unlock tables;
+select * from t1;
+check table t1;
+drop table t1;