Hi, We have suddenly lost 'admin access' to a top-level site (MOSS 2007)! Neither the farm account nor several site admin accounts can be used to administer the site although they appear in 'Site Collection Administrators’. Running “stsadm -o adduser … -siteadmin” result in “Access is denied. (Exception from HRESULT: 0x80070005 (E_ACCESSDENIED))” Any suggestions – please.

Have you tried setting a Web application permission policy in Central admin to grant a user access? I would also check your authentication provider settings. If the authentication provider has been changed for the web application it may no longer be able to authenticate users that were added in the past.Paul Stork SharePoint Server MVP

Hi TRoennow, have you tryed to "repair" your SharePoint Instalation? The stsadm command must be executed with the sharepoint administrator account. Give us some more information about your problem.ML

Hi, This link http://chanakyajayabalan.wordpress.com/2009/12/18/site-collection-quotas-and-locks/ inspired me to look at Site Collection Quotas and Locks and Read-only was checked ! None of the very few users with farm adm permission has changes this setting. Could it happen when a backup job fails?