There has been a new issue surfacing when installing or upgrading to vCenter Server 6.0. The error message seems pretty clear: Incompatible MSSQL version with vCenter Server 6.0. If you dive a little bit deeper and look at additional logs like vminst.log or the CollectRequirements_com.vmware.vcdb_date.log you will see the following entries.
vcsInstUtil-2562624| I: ParsePreUpgradeOutput: Export disk req: 0 MB, Import disk req: 0 MB. vcsInstUtil-2562624| I: PitCA_MessageBox: Displaying message: "Error: Source vCenter Server validation found an issue: ERROR: Incompatible MSSQL version with vCenter Server 6.0 Resolution: Make sure your database is configured to meet vCenter Server upgrade requirements."
ERROR vcdb Error while validating source vCenter Server database: ERROR: Incompatible MSSQL version with vCenter Server 6.0
It is important that you first make sure to check the Interoperability Matrix to ensure that the database you are using is supported. You will need to check the radio box Solution/Database Interoperability and select both VMware vCenter Server and 6.0 from the drop down boxes.
Note: These are not all-inclusive, I just took the top several rows as an example.
You also want to check the database version, and compatibility level; you can do this by running the SQL query below or by using the GUI. You will want to ensure that the compatibility is set to SQL Server 2008 or higher.
SELECT SERVERPROPERTY('productversion'), SERVERPROPERTY ('productlevel'), SERVERPROPERTY ('edition')
Step 1. Open Microsoft SQL Server Management Studio expand Databases Right Click and select Properties
Step 2. Select Options and Ensure the compatibility level is set to SQL Server 2008 or higher
After you change the compatibility level, you should be able to re-run the install or upgrade successfully!