SharePoint Errors “in the field”

 

“An unexpected error has occurred” in central admin

http://stackoverflow.com/questions/1997803/an-unexpected-error-has-occurred

http://sharepointinterface.com/2012/08/30/an-unexpected-error-has-occurred-after-installing-sharepoint-2013/

“Windows SharePoint Services 3” saying: “Access to table dbo.Versions is blocked because the signature is not valid.” 

The issue was a corrupt configuration database, restore config db from backup.