If you need to remove a SSRS SQL Server database instance from Reporting Services Configuration Manager such as due to migrating a RS database from one server to another, you can do so by running the RSKeyMgmt command.
On your Report Server, open a command prompt and enter the following to find the GUID you want to remove.
RSKeyMgmt –l
The above parameter is a lower case “L” not a one. 
That will return your list of machine instances. Mark and copy the GUID of the instance to remove. Then enter the following to remove that instance from that Report Server’s configuration.
RSKeyMgmt –r <GUID>
Yes or No: Y
Now your instance is removed from this RS configuration.
Reference Material: http://msdn.microsoft.com/es-py/library/ms162822(v=SQL.110).aspx
Sadly, Linda, SQL2012 doesn't support this argument in RTM through CU4.
ReplyDeleteI got an error "unable to locate the report server windows service for instance mssqlserver Can u advise
ReplyDeletehi, I also had the same error. How where you able to resolve this?
DeleteSQL 2012 does support the argument actually. The actual SQL instance needs to be specified though.
ReplyDeleteTry using this:
RSKeyMgmt –i "InstanceName" -l