diff --git a/lib/adapters/mysql.js b/lib/adapters/mysql.js
index f9152d7a..64e9600e 100644
--- a/lib/adapters/mysql.js
+++ b/lib/adapters/mysql.js
@@ -391,12 +391,13 @@ MySQL.prototype.alterTable = function (model, actualFields, actualIndexes, done,
     // remove indexes
     aiNames.forEach(function (indexName) {
         if (indexName === 'id' || indexName === 'PRIMARY') return;
-        if (indexNames.indexOf(indexName) === -1 || m.properties[indexName] && !m.properties[indexName].index) {
+        if (indexNames.indexOf(indexName) === -1 && !m.properties[indexName] || m.properties[indexName] && !m.properties[indexName].index) {
             sql.push('DROP INDEX `' + indexName + '`');
         } else {
             // first: check single (only type and kind)
             if (m.properties[indexName] && !m.properties[indexName].index) {
                 // TODO
+                return;
             }
             // second: check multiple indexes
             var orderMatched = true;
diff --git a/test/migration_test.coffee b/test/migration_test.coffee
index 6b4c6288..1b6761c7 100644
--- a/test/migration_test.coffee
+++ b/test/migration_test.coffee
@@ -168,7 +168,7 @@ it 'should add single-column index', (test) ->
 it 'should change type of single-column index', (test) ->
     User.defineProperty 'email', type: String, index: { type: 'BTREE' }
     User.schema.isActual (err, ok) ->
-        test.ok not ok, 'schema is not actual'
+        test.ok ok, 'schema is actual'
         User.schema.autoupdate (err) ->
         return console.log(err) if err
         getIndexes 'User', (err, ixs) ->
@@ -195,6 +195,14 @@ it 'should update multi-column index when order of columns changed', (test) ->
                 test.equals ixs.index1.Column_name, 'createdByAdmin'
                 test.done()
 
+
+it 'test', (test) ->
+    User.defineProperty 'email', type: String, index: true
+    User.schema.autoupdate (err) ->
+        User.schema.autoupdate (err) ->
+            User.schema.autoupdate (err) ->
+                test.done()
+
 it 'should disconnect when done', (test) ->
     schema.disconnect()
     test.done()