When you Uninstall SQl server some of the traces will be left behind one of them are Reporting serivces catalogs in order to fix this issue follow the screen shots below
Next to go to the Sql server root directory, by default
C:Program FilesMicrosoft SQL ServerMSSQL10_50.MSSQLSERVERMSSQLDATA
z
Files to be deleted
- ReportServer.mdf
- ReportServer_log.LDF
- ReportServerTempDB.mdf
- ReportServerTempDB_log.LDF.