Error during execution of statement:
set lock_timeout 10000
declare @ErrorMessage nvarchar(1000)= '50000'+char(9)+'2'+char(9)
if exists (select top 1 1
from sys.tables t
where t.type = 'U'
select @ErrorMessage = concat(@ErrorMessage
, '#LDS#Creating a new master is only allowed on empty databases.|'
raiserror(@ErrorMessage, 18, 2) with nowait
While carrying out upgrade from version 8.0.2 to 8.1.5, via config wizard we are getting the  Database error 50000: Creating a new master is only allowed on empty databases.
Our DB User has sysadmin and db creator access.
Can anyone Please help us , as in what could be the wrong in here ?