diff --git a/mysql-test/r/merge.result b/mysql-test/r/merge.result
index db2c462398f..6e2da3126cd 100644
--- a/mysql-test/r/merge.result
+++ b/mysql-test/r/merge.result
@@ -178,12 +178,12 @@ t3	CREATE TABLE `t3` (
 ) ENGINE=MRG_MyISAM DEFAULT CHARSET=latin1 UNION=(`t1`,`t2`)
 create table t4 (a int not null, b char(10), key(a)) engine=MERGE UNION=(t1,t2);
 select * from t4;
-ERROR HY000: All tables in the MERGE table are not identically defined
+ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exists
 alter table t4 add column c int;
-ERROR HY000: All tables in the MERGE table are not identically defined
+ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exists
 flush tables;
 select * from t4;
-ERROR HY000: All tables in the MERGE table are not identically defined
+ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exists
 create database mysqltest;
 create table mysqltest.t6 (a int not null primary key auto_increment, message char(20));
 create table t5 (a int not null, b char(20), key(a)) engine=MERGE UNION=(test.t1,mysqltest.t6);
@@ -771,6 +771,15 @@ Table	Op	Msg_type	Msg_text
 test.t1	check	status	OK
 test.t2	check	status	OK
 drop table t1, t2, t3;
+CREATE TABLE t1(a INT) ENGINE=MEMORY;
+CREATE TABLE t2(a INT) ENGINE=MERGE UNION=(t1);
+SELECT * FROM t2;
+ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exists
+DROP TABLE t1, t2;
+CREATE TABLE t2(a INT) ENGINE=MERGE UNION=(t3);
+SELECT * FROM t2;
+ERROR HY000: Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exists
+DROP TABLE t2;
 create table t1 (b bit(1));
 create table t2 (b bit(1));
 create table tm (b bit(1)) engine = merge union = (t1,t2);
diff --git a/mysql-test/t/merge.test b/mysql-test/t/merge.test
index f8bed9c92cd..d3a2928608d 100644
--- a/mysql-test/t/merge.test
+++ b/mysql-test/t/merge.test
@@ -381,6 +381,20 @@ select * from t3;
 check table t1, t2;
 drop table t1, t2, t3;
 
+#
+# BUG#10974 - No error message if merge table based on union of innodb,
+# memory
+#
+CREATE TABLE t1(a INT) ENGINE=MEMORY;
+CREATE TABLE t2(a INT) ENGINE=MERGE UNION=(t1);
+--error 1168
+SELECT * FROM t2;
+DROP TABLE t1, t2;
+CREATE TABLE t2(a INT) ENGINE=MERGE UNION=(t3);
+--error 1168
+SELECT * FROM t2;
+DROP TABLE t2;
+
 # End of 4.1 tests
 
 #
diff --git a/sql/share/errmsg.txt b/sql/share/errmsg.txt
index ccbdd3586a2..ff6b8818460 100644
--- a/sql/share/errmsg.txt
+++ b/sql/share/errmsg.txt
@@ -3791,7 +3791,7 @@ ER_WRONG_MRG_TABLE
         cze "V-B¹echny tabulky v MERGE tabulce nejsou definovány stejnì"
         dan "Tabellerne i MERGE er ikke defineret ens"
         nla "Niet alle tabellen in de MERGE tabel hebben identieke gedefinities"
-        eng "All tables in the MERGE table are not identically defined"
+        eng "Unable to open underlying table which is differently defined or of non-MyISAM type or doesn't exists"
         est "Kõik tabelid MERGE tabeli määratluses ei ole identsed"
         fre "Toutes les tables de la table de type MERGE n'ont pas la même définition"
         ger "Nicht alle Tabellen in der MERGE-Tabelle sind gleich definiert"
diff --git a/storage/myisammrg/myrg_open.c b/storage/myisammrg/myrg_open.c
index cf82f13da57..862201ed841 100644
--- a/storage/myisammrg/myrg_open.c
+++ b/storage/myisammrg/myrg_open.c
@@ -90,7 +90,10 @@ MYRG_INFO *myrg_open(const char *name, int mode, int handle_locking)
     else
       fn_format(buff, buff, "", "", 0);
     if (!(isam=mi_open(buff,mode,(handle_locking?HA_OPEN_WAIT_IF_LOCKED:0))))
+    {
+      my_errno= HA_ERR_WRONG_MRG_TABLE_DEF;
       goto err;
+    }
     if (!m_info)                                /* First file */
     {
       key_parts=isam->s->base.key_parts;