Resolving Upgrade Issues
The topics in this section describe upgrade issues that can be detected as well as those that cannot be detected, but that might affect the upgrade or post-upgrade experience. The issues are organized by SQL Server component.
A few configurations or settings in a previous version of SQL Server can prevent you from upgrading to SQL Server 2014. If Setup detects these issues when you install SQL Server 2014, Setup stops the upgrade process and requests that you run Upgrade Advisor and fix any blocking issues.