Issue:
When trying to create a new database, you are receiving the following error but the database is still created in SQL:
NullReferenceException
Object reference not set to an instance of an object.
Cause:
This is caused by attempting to connect to an SQL Server that is lower than 2018 (e.g. SQL Server 2008, 2008 R2).
The reason this fails is SQL Server 2008 R2 became unsupported by Forecast 5 in March 2018 as there are a number of features Forecast 5 uses that are not available in these older version, as per this Microsoft article
Solution:
Upgrade to a supported SQL Server version or install a supported standalone SQL Server Express version.