The login account to install the SQL Server Database Engine doesn't have the necessary permissions to complete the installation.

Manually reinstall SQL Server 2019 using the System account

1. Verify that the Microsoft .NET Framework 3.5 and 4.8 items are installed and enabled on the machine.
2. Make sure you're logged in with a local admin account, not an MSN or passport account
3. Open Windows File Explorer.
4. Browse to the C:\Sage100Con\Downloads folder.
5. In this folder, right-click on SQLEXPRADV_x64_ENU.exe.
6. Choose Run as administrator. Click OK.
7. When the installation window appears, click New SQL Server stand-alone installation.
8. When the pre-checker is finished, click Next.
9. Choose the option "Perform a new installation of SQL Server 2019." Click Next.
10. Select the box to accept license terms and click Next.
11. Click Select All then click Next.
12. When prompted, deselect the items outlined in red as they're not required for Sage 100 Contractor.
    
13. Choose the option for Name instance.
14. Type SAGE100CON in the field and click in the Instance ID: field.
     NOTE: The name of the SQL instance will populate the field.  
15. Click Next.
16. Click the picklist arrow in the Account Name box on the Server Configuration, SQL Server Database Engine line.
17. Click the < > symbol.
18. Type the word "System" (without the quotes) and click OK.
19. Click the Collation tab, next to the Service Accounts tab.
20. The collation should read exactly SQL_Latin1_General_CP1_CI_AS.
21. Click the Customize button.
22. Select SQL_Latin1_General_CP1_CI_AS from the SQL collation picklist.
23. Click OK.
24. Click Next.
25. On the next screen, select Mixed Mode.
26. Enter the "sa" or SQL Administrator password.
     NOTE: This password must be at least eight characters long and begin with a letter, include a number, and a special character.  
27. Click Add Current User.
28. Click Next, then Next again.
29. Continue through the rest of the installation (this will take several minutes).
30. When the installation is complete, click Close and close the installation window.
31. Open and log in to Database Administration for Sage 100 Contractor.