Rename an Analysis Services Instance

This is just a short post for Friday. I have been working a fair amount with SSAS and the rest of the BI stack and recently I was asked to install a default instance of SSAS on server that already had a named instance installed. I didn't think this would take me a long time I had a quick look at Configuration Manager saw the named SSAS instance mounted up the ISO and off I went.

Click click click click done. Oh an Error."The instance ID needs to be unique please " on further investigation it seemed that the existing named instance had the default instance ID. How could that be I thought?