This error appears during Microsoft SQL Server installation. If you have previously installed eWay-CRM or other software that uses Microsoft SQL Server, there could remain files on your hard drive that prevent the installation of newer version of Microsoft SQL Server.
All versions of eWay-CRM
Using Windows File Explorer, go to this location on your hard drive: C:\Program Files\Microsoft SQL Server. If you have 64-bit system, the location is following: C:\Program Files (x86)\Microsoft SQL Server. There should be MSSQL.X folder (X is a number of SQL Server instance. Mostly, there will be "MSSQL.1". Rename this folder on "_MSSQL.1" for easier identification. Now, you can launch the eWay-CRM installation.