Mary,

Thanks for your quick and thorough response.

1. As noted in my post, I've already updated to the latest version of Quickbooks, and that didn't fix the issue.
2. As you suggested, I tried logging into a sample company to test if the issue occurs there, and I confirmed that the error also does occur when using the sample company data.
3. I do have SQL Server 2012 ("Express" version - which is a free version commonly used by other apps) installed on my workstation, and it's being used by another application. Therefore, uninstalling it is not an option for me.

I'm disappointed about #3 as it applies to my situation. This really makes no sense. Why would all other areas of Quickbooks 2018 save data without problems, but this ONE feature breaks because SQL Server is present on my system? Is there any other solution besides uninstalling SQL Server?