Make sure that Microsoft KB 2653857 is applied on the SQL Server. If that is not possible, before you upgrade, disable SQL Force Encryption if it is enabled:

1. Open SQL Server Configuration Manager for the SQL instance that hosts the ePO database.
2. Right-click Protocols for (MSSQLSERVER by default) under SQL Server Network Configuration, and click Properties.
3. From the Force Encryption drop-down list, select No.
4. Click OK.
5. Restart the SQL instance that hosts the ePO database, for the change to take effect.

After the upgrade is complete, you can re-enable the Force Encryption option, and verify if ePO can connect to the database. If it can't, you need leave force encryption set to No, until you can apply KB 2653857 on the server that hosts SQL Server database.