diff --git a/phpBB/install/convertors/convert_phpbb20.php b/phpBB/install/convertors/convert_phpbb20.php
index fac58a7d7d..6c55a42440 100644
--- a/phpBB/install/convertors/convert_phpbb20.php
+++ b/phpBB/install/convertors/convert_phpbb20.php
@@ -314,6 +314,7 @@ if (!$get_info)
 				'target'		=> (defined('MOD_ATTACHMENT')) ? ATTACHMENTS_TABLE : '',
 				'primary'		=> 'attachments.attach_id',
 				'query_first'	=> (defined('MOD_ATTACHMENT')) ? $convert->truncate_statement . ATTACHMENTS_TABLE : '',
+				'autoincrement'	=> 'attach_id',
 
 				array('attach_id',				'attachments.attach_id',				''),
 				array('post_msg_id',			'attachments.post_id',					''),
@@ -338,6 +339,7 @@ if (!$get_info)
 			array(
 				'target'		=> (defined('MOD_ATTACHMENT')) ? ATTACHMENTS_TABLE : '',
 				'primary'		=> 'attachments.attach_id',
+				'autoincrement'	=> 'attach_id',
 
 				array('attach_id',				'attachments.attach_id',				''),
 				array('post_msg_id',			'attachments.privmsgs_id',				''),
@@ -362,6 +364,7 @@ if (!$get_info)
 			array(
 				'target'		=> (defined('MOD_ATTACHMENT')) ? EXTENSIONS_TABLE : '',
 				'query_first'	=> (defined('MOD_ATTACHMENT')) ? $convert->truncate_statement . EXTENSIONS_TABLE : '',
+				'autoincrement'	=> 'extension_id',
 
 				array('extension_id',			'extensions.ext_id',				''),
 				array('group_id',				'extensions.group_id',				''),
@@ -371,6 +374,7 @@ if (!$get_info)
 			array(
 				'target'		=> (defined('MOD_ATTACHMENT')) ? EXTENSION_GROUPS_TABLE : '',
 				'query_first'	=> (defined('MOD_ATTACHMENT')) ? $convert->truncate_statement . EXTENSION_GROUPS_TABLE : '',
+				'autoincrement'	=> 'group_id',
 
 				array('group_id',				'extension_groups.group_id',			''),
 				array('group_name',				'extension_groups.group_name',			array('function1' => 'phpbb_set_encoding', 'function2' => 'utf8_htmlspecialchars')),
@@ -414,6 +418,7 @@ if (!$get_info)
 			array(
 				'target'		=> RANKS_TABLE,
 				'query_first'	=> $convert->truncate_statement . RANKS_TABLE,
+				'autoincrement'	=> 'rank_id',
 
 				array('rank_id',					'ranks.rank_id',				''),
 				array('rank_title',					'ranks.rank_title',				array('function1' => 'phpbb_set_encoding', 'function2' => 'utf8_htmlspecialchars')),
@@ -426,6 +431,7 @@ if (!$get_info)
 				'target'		=> TOPICS_TABLE,
 				'query_first'	=> $convert->truncate_statement . TOPICS_TABLE,
 				'primary'		=> 'topics.topic_id',
+				'autoincrement'	=> 'topic_id',
 
 				array('topic_id',				'topics.topic_id',					''),
 				array('forum_id',				'topics.forum_id',					''),
@@ -456,6 +462,7 @@ if (!$get_info)
 			array(
 				'target'		=> TOPICS_TABLE,
 				'primary'		=> 'topics.topic_id',
+				'autoincrement'	=> 'topic_id',
 
 				array('topic_id',				'topics.topic_id',					''),
 				array('forum_id',				'topics.forum_id',					''),
@@ -496,6 +503,7 @@ if (!$get_info)
 			array(
 				'target'		=> SMILIES_TABLE,
 				'query_first'	=> $convert->truncate_statement . SMILIES_TABLE,
+				'autoincrement'	=> 'smiley_id',
 
 				array('smiley_id',				'smilies.smilies_id',				''),
 				array('code',					'smilies.code',						'phpbb_set_encoding'),
@@ -543,6 +551,7 @@ if (!$get_info)
 				'target'		=> WORDS_TABLE,
 				'primary'		=> 'words.word_id',
 				'query_first'	=> $convert->truncate_statement . WORDS_TABLE,
+				'autoincrement'	=> 'word_id',
 
 				array('word_id',				'words.word_id',					''),
 				array('word',					'words.word',						'phpbb_set_encoding'),
@@ -552,6 +561,7 @@ if (!$get_info)
 			array(
 				'target'		=> POSTS_TABLE,
 				'primary'		=> 'posts.post_id',
+				'autoincrement'	=> 'post_id',
 				'query_first'	=> $convert->truncate_statement . POSTS_TABLE,
 				'execute_first'	=> '
 					$config["max_post_chars"] = 0;
@@ -595,6 +605,7 @@ if (!$get_info)
 			array(
 				'target'		=> PRIVMSGS_TABLE,
 				'primary'		=> 'privmsgs.privmsgs_id',
+				'autoincrement'	=> 'privmsgs_id',
 				'query_first'	=> array(
 					$convert->truncate_statement . PRIVMSGS_TABLE,
 					$convert->truncate_statement . PRIVMSGS_RULES_TABLE,
@@ -741,6 +752,7 @@ if (!$get_info)
 
 			array(
 				'target'		=> GROUPS_TABLE,
+				'autoincrement'	=> 'group_id',
 				'query_first'	=> $convert->truncate_statement . GROUPS_TABLE,
 
 				array('group_id',				'groups.group_id',					''),
@@ -781,6 +793,7 @@ if (!$get_info)
 			array(
 				'target'		=> USERS_TABLE,
 				'primary'		=> 'users.user_id',
+				'autoincrement'	=> 'user_id',
 				'query_first'	=> array(
 					'DELETE FROM ' . USERS_TABLE . ' WHERE user_id <> ' . ANONYMOUS,
 					$convert->truncate_statement . BOTS_TABLE
diff --git a/phpBB/install/install_convert.php b/phpBB/install/install_convert.php
index 4636bbeecc..0d1fec4a1c 100644
--- a/phpBB/install/install_convert.php
+++ b/phpBB/install/install_convert.php
@@ -910,48 +910,13 @@ class install_convert extends module
 					}
 				}
 
-				if ($db->sql_layer === 'postgres')
+				if (!empty($schema['autoincrement']))
 				{
-					$tables = array(
-						ATTACHMENTS_TABLE => 'attach_id',
-						ACL_OPTIONS_TABLE => 'auth_option_id',
-						ACL_ROLES_TABLE => 'role_id',
-						BANLIST_TABLE => 'ban_id',
-						BOTS_TABLE => 'bot_id',
-						DISALLOW_TABLE => 'disallow_id',
-						DRAFTS_TABLE => 'draft_id',
-						EXTENSIONS_TABLE => 'extension_id',
-						EXTENSION_GROUPS_TABLE => 'group_id',
-						FORUMS_TABLE => 'forum_id',
-						GROUPS_TABLE => 'group_id',
-						ICONS_TABLE => 'icons_id',
-						LANG_TABLE => 'lang_id',
-						LOG_TABLE => 'log_id',
-						MODULES_TABLE => 'module_id',
-						POSTS_TABLE => 'post_id',
-						PRIVMSGS_TABLE => 'msg_id',
-						PRIVMSGS_FOLDER_TABLE => 'folder_id',
-						PRIVMSGS_RULES_TABLE => 'rule_id',
-						PROFILE_FIELDS_TABLE => 'field_id',
-						RANKS_TABLE => 'rank_id',
-						REPORTS_TABLE => 'report_id',
-						REPORTS_REASONS_TABLE => 'reason_id',
-						SEARCH_WORDLIST_TABLE => 'word_id',
-						SITELIST_TABLE => 'site_id',
-						SMILIES_TABLE => 'smiley_id',
-						STYLES_TABLE => 'style_id',
-						STYLES_TEMPLATE_TABLE => 'template_id',
-						STYLES_TEMPLATE_DATA_TABLE => 'template_id',
-						STYLES_THEME_TABLE => 'theme_id',
-						STYLES_IMAGESET_TABLE => 'imageset_id',
-						TOPICS_TABLE => 'topic_id',
-						USERS_TABLE => 'user_id',
-						WARNINGS_TABLE => 'warning_id',
-						WORDS_TABLE => 'word_id'
-					);
-					if (!empty($tables[$schema['target']]))
+					switch ($db->sql_layer)
 					{
-						$db->sql_query("SELECT SETVAL('" . $schema['target'] . "_seq',(select case when max(" . $tables[$schema['target']] . ")>0 then max(" . $tables[$schema['target']] . ")+1 else 1 end from " . $schema['target'] . '));');
+						case 'postgres':
+							$db->sql_query("SELECT SETVAL('" . $schema['target'] . "_seq',(select case when max(" . $schema['autoincrement'] . ")>0 then max(" . $schema['autoincrement'] . ")+1 else 1 end from " . $schema['target'] . '));');
+						break;
 					}
 				}
 			}
@@ -1051,6 +1016,17 @@ class install_convert extends module
 
 				$convert->row = $convert_row = array();
 
+				if (!empty($schema['autoincrement']))
+				{
+					switch ($db->sql_layer)
+					{
+						case 'mssql':
+						case 'mssql_odbc':
+							$db->sql_query('SET IDENTITY_INSERT ' . $schema['target'] . ' ON');
+						break;
+					}
+				}
+
 				// Now handle the rows until time is over or no more rows to process...
 				while (still_on_time())
 				{
@@ -1168,48 +1144,18 @@ class install_convert extends module
 					$waiting_rows = array();
 				}
 
-				if ($db->sql_layer === 'postgres')
+				if (!empty($schema['autoincrement']))
 				{
-					$tables = array(
-						ATTACHMENTS_TABLE => 'attach_id',
-						ACL_OPTIONS_TABLE => 'auth_option_id',
-						ACL_ROLES_TABLE => 'role_id',
-						BANLIST_TABLE => 'ban_id',
-						BOTS_TABLE => 'bot_id',
-						DISALLOW_TABLE => 'disallow_id',
-						DRAFTS_TABLE => 'draft_id',
-						EXTENSIONS_TABLE => 'extension_id',
-						EXTENSION_GROUPS_TABLE => 'group_id',
-						FORUMS_TABLE => 'forum_id',
-						GROUPS_TABLE => 'group_id',
-						ICONS_TABLE => 'icons_id',
-						LANG_TABLE => 'lang_id',
-						LOG_TABLE => 'log_id',
-						MODULES_TABLE => 'module_id',
-						POSTS_TABLE => 'post_id',
-						PRIVMSGS_TABLE => 'msg_id',
-						PRIVMSGS_FOLDER_TABLE => 'folder_id',
-						PRIVMSGS_RULES_TABLE => 'rule_id',
-						PROFILE_FIELDS_TABLE => 'field_id',
-						RANKS_TABLE => 'rank_id',
-						REPORTS_TABLE => 'report_id',
-						REPORTS_REASONS_TABLE => 'reason_id',
-						SEARCH_WORDLIST_TABLE => 'word_id',
-						SITELIST_TABLE => 'site_id',
-						SMILIES_TABLE => 'smiley_id',
-						STYLES_TABLE => 'style_id',
-						STYLES_TEMPLATE_TABLE => 'template_id',
-						STYLES_TEMPLATE_DATA_TABLE => 'template_id',
-						STYLES_THEME_TABLE => 'theme_id',
-						STYLES_IMAGESET_TABLE => 'imageset_id',
-						TOPICS_TABLE => 'topic_id',
-						USERS_TABLE => 'user_id',
-						WARNINGS_TABLE => 'warning_id',
-						WORDS_TABLE => 'word_id'
-					);
-					if (!empty($tables[$schema['target']]))
+					switch ($db->sql_layer)
 					{
-						$db->sql_query("SELECT SETVAL('" . $schema['target'] . "_seq',(select case when max(" . $tables[$schema['target']] . ")>0 then max(" . $tables[$schema['target']] . ")+1 else 1 end from " . $schema['target'] . '));');
+						case 'mssql':
+						case 'mssql_odbc':
+							$db->sql_query('SET IDENTITY_INSERT ' . $schema['target'] . ' OFF');
+						break;
+
+						case 'postgres':
+							$db->sql_query("SELECT SETVAL('" . $schema['target'] . "_seq',(select case when max(" . $schema['autoincrement'] . ")>0 then max(" . $schema['autoincrement'] . ")+1 else 1 end from " . $schema['target'] . '));');
+						break;
 					}
 				}
 			}