SQL Server Express is not officially certified with CA Client Automation.
Please refer the CA Client Automation compatibility matrix below for more info:
There are several limitations in SQL Server Express edition:
Max CPU: 1
Max Memory per instance: 1 GB
Max Database size: 10GB (data file size only)
The installation of CA Client Automation on SQL Server Express should work since the express version has the same code as the standard and enterprise versions. However, due to the limitations outlined above (10GB per database and 1GB RAM), there could be several performance issues.
Therefore, SQL Server Express edition is not certified and we don't support it officially.