Hello,

I just unistalled thie extension and now I want to reinstalled. But I face this erro
Error building Admin Menus
Component Install: DB function reports no errors
Failed deleting joomsef.xml
Failed deleting joomsef.php


I already deleted all tables of this extention.

Hi,
Try manually deleting the /componenets/com_sef and /administrator/components/com_sef directories. Then delete the /plugins/system/joomsef, joomsefgoogle and joomseflang plugins and /plugins/content/joomsef plugin.
Then open the _extensions table in your Joomla database and delete all the entries for deleted plugins and also delete entries for JoomSEF extensions (type = sef_ext).
Then open the _menu table in Joomla database and delete all entries with titles starting with COM_SEF.

After this try installing JoomSEF again.

UPDATE: Of course make sure you have the current backup of your website prior to doing this!