I tried to change the authentication of one of the site collection to use claim based authentication and I did that through power shell. After I finished, the site settings link disappeared from the site action for Admin user. How can I get it back ? site content only there on site action. I do reset the site form the IIS but with no result.
Note, this site is not allowing some of the users to access it despite they have contribute privilege. Some of them can access the site while others got access denied and they all have the same privilege. For that I tried some of the commands on the power shell to use claim based authentication and it actually used it.